OUC离散数学II实验二（Python+Cpp）

实验主题

生成树、环路空间、断集空间的求解

实验目的

1、掌握无向连通图生成树的求解方法；

2、掌握基本回路系统和环路空间的求解方法；

3、掌握基本割集系统和断集空间的求解方法；

4、了解生成树、环路空间和断集空间的实际应用。

实验要求

给定一无向简单连通图的相邻矩阵 （例如：)。

1、输出此图的关联矩阵M。

2、求此图所有生成树个数。

3、输出其中任意一棵生成树的相邻矩阵（默认第i行对应顶点vi）和关联矩阵（默认第i行对应顶点vi，第j列对应边ej）。

4、求此生成树对应的基本回路系统（输出形式如：{e1e4e3,e2e5e3}）。

5、求此生成树对应的环路空间（输出形式如：{Φ,e1e4e3,e2e5e3,e1e4e5e2}）。

6、求此生成树对应的基本割集系统（输出形式如：{{e1,e4},{e2,e5},{e3,e4,e5}}）。

7、求此生成树对应的断集空间（输出形式如：{Φ,{e1,e4},{e2,e5},{e3,e4,e5},{e1,e2,e4,e5},{e1,e3,e5},{e2,e3,e4},{e1,e2,e3}}）。

实验内容

1. 输出关联矩阵

在相邻矩阵中，如果不为0，则表示这两点之间有边，如果大于1，表示有平行边，可以对相邻矩阵的每一行遍历，找到不为0的元素时，在新矩阵中新增一行，其中两点对应的位置置1，表示一条边，并同时将该元素和其关于主对角线元素-1，最后将矩阵输出即可。

def guanlian_matrix(l: list) -> list:
    length = len(l)
    lc = copy.deepcopy(l)
    m = []
    for i in range(length):
        for j in range(length):
            if lc[i][j] > 0:
                for k in range(lc[i][j]):
                    t = [0] * length
                    t[i], t[j] = 1, 1
                    m.append(t)
                    lc[i][j] -= 1
                    lc[j][i] -= 1
    return m

输出：

print("===>关联矩阵")
g = guanlian_matrix(m)
print("   ", end="")
[print('e' + str(i), end="\t") for i in range(len(g))]
print()
for i in range(len(g[0])):
    print("v" + str(i), end="  ")
    for j in range(len(g)):
        print(g[j][i], end="\t")
    print()

2. 求生成树的个数

方法一：

设D(G)为图的度对角矩阵，A(G)为图的领接矩阵，则C = D ( G ) − A ( G ) 的任意一个余子式的值即为图G的生成树个数。C也成为拉式矩阵。分析得，拉式矩阵的对角线上的元素为相邻矩阵对应行上所有元素的求和，其他为相邻矩阵的相反数。得到拉式矩阵后，再取第一行第一列的余子式，也就是去除第一行和第一列的行列式。

求行列式，可以采用定义法，按第一行展开，得到的n个代数余子式，同样也是求行列式，再按照其第一行展开，一直递归到只剩一行时结束，即可算出行列式。这里使用了numpy中的函数实现。

def cal_tree(l: list) -> int:
    m = []
    for i in range(1, len(l)):
        t = []
        for j in range(1, len(l)):
            if i == j:
                t.append(sum(l[i]))
            else:
                t.append(-l[i][j])
        m.append(t)
    return int(round(np.linalg.det(np.array(m)), 0))

方法二：

可以去除关联矩阵中的任意一行，得到一个n-1行m列的矩阵，再在m条边中选择n-1条，组成一个新矩阵，计算该矩阵是否满秩，即计算行列式是否为0，如果不为0，则包含一个生成树。

def cal_tree(l: list) -> int:
    x = list(itertools.combinations(range(len(l)), len(l[0]) - 1))
    n = 0
    for each in x:
        matrix = [l[i][1:] for i in each]
        if np.linalg.det(matrix) != 0:
            n += 1
    return n

3. 输出一颗树的相邻矩阵和关联矩阵

利用上一题的方法二，取出其中的一个结果，其中从m中选出的n-1列就是选出的树枝。

对于排列组合，可以采用二进制枚举，从1 ~ 2ⁿ⁺¹-1判断二进制数中有多少个1，如果符合需要组合的个数，则储存起来，其中1表示被选中，0表示不被选中。这里使用了itertools中的combination函数实现。

def tree(l: list) -> tuple:
    x = list(itertools.combinations(range(len(l)), len(l[0]) - 1))
    rep = []
    for each in x:
        matrix = [l[i][1:] for i in each]
        if np.linalg.det(matrix) != 0:
            rep = each
            break
    xianglin = [[0] * len(l[0]) for _ in range(len(l[0]))]
    guanlian = [l[i] for i in rep]
    # 根据关联矩阵计算相邻矩阵
    for i in guanlian:
        e = [j for j in range(len(i)) if i[j] == 1]
        xianglin[e[0]][e[1]], xianglin[e[1]][e[0]] = 1, 1
    return xianglin, guanlian, rep

输出：

x, y, bian = tree(g)
print("===>生成树的相邻矩阵")
print("   ", end="")
[print('v' + str(i), end="\t") for i in range(len(x))]
print()
for i in range(len(x)):
    print("v" + str(i), end="  ")
    for j in range(len(x)):
        print(x[j][i], end="\t")
    print()

print("===>生成树关联矩阵")
print("   ", end="")
[print('e' + str(i), end=" ") for i in bian]
print()
for i in range(len(y[0])):
    print("v" + str(i), end="  ")
    for j in range(len(y)):
        print(y[j][i], end="  ")
    print()

4. 求生成树对应的基本回路系统

根据生成树的边，可以求出该生成树对应的弦，再根据每根弦的两个顶点，在生成树找到两个顶点的一条通路，加上这条弦，构成一条回路，于是可以求出基本回路系统。寻找通路时，采用了BFS宽度优先搜索，以生成树中的一个顶点为根节点，搜索时保存其子节点，最后再根据保存的字节点，为每个字节点的父节点赋值。根据另一个点，向回找到根节点即为一条回路。

class Node:
    def __init__(self, num, pre=None):
        self.pre = pre
        self.num = num
        self.succed = []


def bfs_loop(matrix: list, start: int, end: int):
    points = [Node(i) for i in range(len(matrix))]
    visited = [False] * len(matrix)
    visited[start] = True
    queue = [start]
    # bfs搜索
    while queue:
        now = queue.pop(0)
        if now == end:
            break
        for i in range(len(matrix)):
            if matrix[now][i] == 1 and visited[i] == False:
                points[now].succed.append(points[i])
                queue.append(i)
                visited[i] = True
    # 为所有字节点的pre赋值，方便找到父节点
    for each in points:
        for i in each.succed:
            i.pre = each
    e = [end]
    # 从端点向回找，找到根节点结束
    while points[end].pre:
        end = points[end].pre.num
        e.insert(0, end)
    return e


def loop(tree: list, guanlian: list, bian: list):
    xian = list(set(range(len(guanlian))) - set(bian))
    loops = []
    # 计算每条弦的回路中的点
    for each in xian:
        e = [i for i in range(len(guanlian[0])) if guanlian[each][i] == 1]
        x = bfs_loop(tree, e[0], e[1])
        x.append(e[0])
        loops.append(x)
    rep = []
    # 根据回路中的点求出对应的边
    for each in loops:
        n = 1
        x = []
        while n < len(each):
            t = [0] * len(guanlian[0])
            t[each[n - 1]], t[each[n]] = 1, 1
            for i in range(len(guanlian)):
                if guanlian[i] == t:
                    x.append('e' + str(i))
                    break
            n += 1
        rep.append(x)
    return rep

5. 求此生成树对应的基本割集系统

可以对每一条树枝，先删除这条树枝，再以此加入弦，如果加入弦之后，图连通，则该弦应该再这条树枝生成的割集中，否则不在。判断连通，可以通过图的相邻矩阵进行bfs搜索，如果全部节点都被访问过的话，则为连通的。也可以使用实验一的方法。

def liantong(matrix: list) -> bool:
    visited = [False] * len(matrix)
    visited[0] = True
    queue = [0]
    # bfs搜索
    while queue:
        now = queue.pop(0)
        for i in range(len(matrix)):
            if matrix[now][i] == 1 and visited[i] == False:
                queue.append(i)
                visited[i] = True
    return all(visited)


def geji(xianglin: list, bian: list, guanlian: list):
    xian = list(set(range(len(guanlian))) - set(bian))
    rep = []

    for i in range(len(bian)):
        xianglin1 = copy.deepcopy(xianglin)
        # 删除树枝
        e = [_ for _ in range(len(guanlian[0])) if guanlian[bian[i]][_] == 1]
        xianglin1[e[0]][e[1]], xianglin1[e[1]][e[0]] = 0, 0
        x = ['e' + str(bian[i])]
        for each in xian:
            # 加上一条弦
            e = [_ for _ in range(len(guanlian[0])) if guanlian[each][_] == 1]
            xianglin1[e[0]][e[1]], xianglin1[e[1]][e[0]] = 1, 1
            if liantong(xianglin1):
                # 如果连通则去除该弦，并加入割集
                x.append('e' + str(each))
                e = [_ for _ in range(len(guanlian[0])) if guanlian[each][_] == 1]
                xianglin1[e[0]][e[1]], xianglin1[e[1]][e[0]] = 0, 0
        rep.append(x)
    return rep

6. 环路空间和断集空间

环路空间只需要对生成树的基本回路系统中取若干个（1~n）做环合运算即可得到结果。环合运算可以取取出的若干个中的第一个回路生成数组A，对于后面的每一个回路，如果其中有边在A中，则在A中删除这条边，如果没有则在A中加入这条边。

取若干个的操作可以使用二进制枚举法，从1~2ⁿ-1，1为被选中，0为不被选中，即可枚举出所有选择的情况，这里使用itertools中的combination实现。

割集空间与环路空间同理。

def space(circles: list):
    rep = copy.deepcopy(circles)
    for i in range(2, len(circles) + 1):
        x = itertools.combinations(range(len(circles)), i)
        for e in x:
            t = copy.deepcopy(circles[e[0]])
            for j in e[1:]:
                for each in circles[j]:
                    if each in t:
                        t.remove(each)
                    else:
                        t.append(each)
            if t not in rep:
                rep.append(t)
    return rep

实验测试数据、代码及相关结果分析

===>关联矩阵
   e0	e1	e2	e3	e4	e5	e6	
v0  1	1	1	0	0	0	0	
v1  1	0	0	1	1	0	0	
v2  0	1	0	1	0	1	0	
v3  0	0	0	0	0	1	1	
v4  0	0	1	0	1	0	1	
共有24颗树
===>生成树的相邻矩阵
   v0	v1	v2	v3	v4	
v0  0	1	1	0	1	
v1  1	0	0	0	0	
v2  1	0	0	1	0	
v3  0	0	1	0	0	
v4  1	0	0	0	0	
===>生成树关联矩阵
   e0 e1 e2 e5 
v0  1  1  1  0  
v1  1  0  0  0  
v2  0  1  0  1  
v3  0  0  0  1  
v4  0  0  1  0  
===>基本回路系统
{ e0e1e3,e0e2e4,e5e1e2e6  }
===>环路空间
{ Φ, e0e1e3, e0e2e4, e5e1e2e6, e1e3e2e4, e0e3e5e2e6, e0e4e5e1e6, e3e4e5e6 }
===>基本割集系统
{ { e0,e3,e4 }, { e1,e3,e6 }, { e2,e4,e6 }, { e5,e6 } }
===>断集空间
{ Φ, { e0,e3,e4 }, { e1,e3,e6 }, { e2,e4,e6 }, { e5,e6 }, { e0,e4,e1,e6 }, { e0,e3,e2,e6 }, { e0,e3,e4,e5,e6 }, { e1,e3,e2,e4 }, { e1,e3,e5 }, { e2,e4,e5 }, { e0,e1,e2 }, { e0,e4,e1,e5 }, { e0,e3,e2,e5 }, { e1,e3,e2,e4,e5,e6 }, { e0,e1,e2,e5,e6 } }

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实验代码

Python

import numpy as np
import copy
import itertools


def guanlian_matrix(l: list) -> list:
    length = len(l)
    lc = copy.deepcopy(l)
    m = []
    for i in range(length):
        for j in range(length):
            if lc[i][j] > 0:
                for k in range(lc[i][j]):
                    t = [0] * length
                    t[i], t[j] = 1, 1
                    m.append(t)
                    lc[i][j] -= 1
                    lc[j][i] -= 1
    return m


def cal_tree(l: list) -> int:
    m = []
    for i in range(1, len(l)):
        t = []
        for j in range(1, len(l)):
            if i == j:
                t.append(sum(l[i]))
            else:
                t.append(-l[i][j])
        m.append(t)
    return int(round(np.linalg.det(np.array(m)), 0))


# def cal_tree(l: list):
#     x = list(itertools.combinations(range(len(l)), len(l[0]) - 1))
#     n = 0
#     for each in x:
#         matrix = [l[i][1:] for i in each]
#         if np.linalg.det(matrix) != 0:
#             n += 1
#     return n

def tree(l: list) -> tuple:
    x = list(itertools.combinations(range(len(l)), len(l[0]) - 1))
    rep = []
    for each in x:
        matrix = [l[i][1:] for i in each]
        if np.linalg.det(matrix) != 0:
            rep = each
            break
    xianglin = [[0] * len(l[0]) for _ in range(len(l[0]))]
    guanlian = [l[i] for i in rep]
    for i in guanlian:
        e = [j for j in range(len(i)) if i[j] == 1]
        xianglin[e[0]][e[1]], xianglin[e[1]][e[0]] = 1, 1
    return xianglin, guanlian, rep


class Node:
    def __init__(self, num, pre=None):
        self.pre = pre
        self.num = num
        self.succed = []


def bfs_loop(matrix: list, start: int, end: int):
    points = [Node(i) for i in range(len(matrix))]
    visited = [False] * len(matrix)
    visited[start] = True
    queue = [start]
    # bfs搜索
    while queue:
        now = queue.pop(0)
        if now == end:
            break
        for i in range(len(matrix)):
            if matrix[now][i] == 1 and visited[i] == False:
                points[now].succed.append(points[i])
                queue.append(i)
                visited[i] = True
    # 为所有字节点的pre赋值，方便找到父节点
    for each in points:
        for i in each.succed:
            i.pre = each
    e = [end]
    # 从端点向回找，找到根节点结束
    while points[end].pre:
        end = points[end].pre.num
        e.insert(0, end)
    return e


def loop(tree: list, guanlian: list, bian: list):
    xian = list(set(range(len(guanlian))) - set(bian))
    loops = []
    # 计算每条弦的回路中的点
    for each in xian:
        e = [i for i in range(len(guanlian[0])) if guanlian[each][i] == 1]
        x = bfs_loop(tree, e[0], e[1])
        x.append(e[0])
        loops.append(x)
    rep = []
    # 根据回路中的点求出对应的边
    for each in loops:
        n = 1
        x = []
        while n < len(each):
            t = [0] * len(guanlian[0])
            t[each[n - 1]], t[each[n]] = 1, 1
            for i in range(len(guanlian)):
                if guanlian[i] == t:
                    x.append('e' + str(i))
                    break
            n += 1
        rep.append(x)
    return rep


def space(circles: list):
    rep = copy.deepcopy(circles)
    for i in range(2, len(circles) + 1):
        x = itertools.combinations(range(len(circles)), i)
        for e in x:
            t = copy.deepcopy(circles[e[0]])
            for j in e[1:]:
                for each in circles[j]:
                    if each in t:
                        t.remove(each)
                    else:
                        t.append(each)
            if t not in rep:
                rep.append(t)
    return rep


def liantong(matrix: list) -> bool:
    visited = [False] * len(matrix)
    visited[0] = True
    queue = [0]
    # bfs搜索
    while queue:
        now = queue.pop(0)
        for i in range(len(matrix)):
            if matrix[now][i] == 1 and visited[i] == False:
                queue.append(i)
                visited[i] = True
    return all(visited)


def geji(xianglin: list, bian: list, guanlian: list):
    xian = list(set(range(len(guanlian))) - set(bian))
    rep = []

    for i in range(len(bian)):
        xianglin1 = copy.deepcopy(xianglin)
        # 删除树枝
        e = [_ for _ in range(len(guanlian[0])) if guanlian[bian[i]][_] == 1]
        xianglin1[e[0]][e[1]], xianglin1[e[1]][e[0]] = 0, 0
        x = ['e' + str(bian[i])]
        for each in xian:
            # 加上一条弦
            e = [_ for _ in range(len(guanlian[0])) if guanlian[each][_] == 1]
            xianglin1[e[0]][e[1]], xianglin1[e[1]][e[0]] = 1, 1
            if liantong(xianglin1):
                # 如果连通则去除该弦，并加入割集
                x.append('e' + str(each))
                e = [_ for _ in range(len(guanlian[0])) if guanlian[each][_] == 1]
                xianglin1[e[0]][e[1]], xianglin1[e[1]][e[0]] = 0, 0
        rep.append(x)
    return rep


m = []
x = input()
while x:
    m.append(list(map(int, x.split())))
    x = input()

print("===>关联矩阵")
g = guanlian_matrix(m)
print("   ", end="")
[print('e' + str(i), end="\t") for i in range(len(g))]
print()
for i in range(len(g[0])):
    print("v" + str(i), end="  ")
    for j in range(len(g)):
        print(g[j][i], end="\t")
    print()

tree_num = cal_tree(m)
print(f"共有{tree_num}颗树")

x, y, bian = tree(g)
print("===>生成树的相邻矩阵")
print("   ", end="")
[print('v' + str(i), end="\t") for i in range(len(x))]
print()
for i in range(len(x)):
    print("v" + str(i), end="  ")
    for j in range(len(x)):
        print(x[j][i], end="\t")
    print()

print("===>生成树关联矩阵")
print("   ", end="")
[print('e' + str(i), end=" ") for i in bian]
print()
for i in range(len(y[0])):
    print("v" + str(i), end="  ")
    for j in range(len(y)):
        print(y[j][i], end="  ")
    print()

print("===>基本回路系统")
circles = loop(x, g, bian)
print("{ ", end="")
for i in range(len(circles)):
    if i != len(circles) - 1:
        print(''.join(circles[i]), end=",")
    else:
        print(''.join(circles[i]), end=" ")
print(" }")

print("===>环路空间")
print("{ Φ, ", end="")
huanlu = space(circles)
for i in range(len(huanlu)):
    if i != len(huanlu) - 1:
        print(''.join(huanlu[i]), end=", ")
    else:
        print(''.join(huanlu[i]), end="")

print(" }")

print("===>基本割集系统")
gj = geji(x, bian, g)
print("{ ", end="")
for i in range(len(gj)):
    print("{ ", end="")
    if i != len(gj) - 1:
        print(','.join(gj[i]), end=" }, ")
    else:
        print(','.join(gj[i]), end=" }")
print(" }")

print("===>断集空间")
dj = space(gj)
print("{ Φ, ", end="")
for i in range(len(dj)):
    print("{ ", end="")
    if i != len(dj) - 1:
        print(','.join(dj[i]), end=" }, ")
    else:
        print(','.join(dj[i]), end=" }")
print(" }")

CPP

#include "iostream"
#include "vector"
#include "cmath"
#include "queue"
#include "algorithm"

using namespace std;

vector<vector<int>> guanlianMatrix(vector<vector<int>> l) {
    vector<vector<int>> t;
    for (int i = 0; i < l.size(); i++) {
        for (int j = 0; j < l.size(); j++) {
            if (l[i][j] > 0) {
                for (int k = 0; k < l[i][j]; k++) {
                    vector<int> line;
                    line.assign(l.size(), 0);
                    line[i] = 1;
                    line[j] = 1;
                    t.push_back(line);
                    l[i][j]--;
                    l[j][i]--;
                }
            }
        }
    }
    return t;
}

//获得det[i][j]余子式行列式
vector<vector<int> > complementMinor(vector<vector<int>> det, int i, int j) {

    int n = det.size();//n为det的行，m为det的列；
    vector<vector<int>> ans(n - 1);//保存获得的结果
    for (int k = 0; k < n - 1; k++)
        for (int l = 0; l < n - 1; l++) {
            ans[k].push_back(det[k < i ? k : k + 1][l < j ? l : l + 1]);
        }
    return ans;
}

int Det(vector<vector<int>> det) {
    int ans = 0;
    int n = det.size(), m = det[0].size();//n为det的行，m为det的列；
    if (n != m) {
        exit(1);
    }
    if (det.size() == 1)
        return det[0][0];

    for (int i = 0; i < m; i++) {
        ans += det[0][i] * pow(-1, i) * Det(complementMinor(det, 0, i));
    }
    return ans;
}

int treeNum(vector<vector<int>> l) {
    vector<vector<int>> m;
    for (int i = 1; i < l.size(); i++) {
        vector<int> t;
        for (int j = 1; j < l.size(); j++) {
            if (i == j) {
                int sum = 0;
                for (int k: l[j]) {
                    sum += k;
                }
                t.push_back(sum);
            } else {
                t.push_back(-l[i][j]);
            }
        }
        m.push_back(t);
    }
    return Det(m);
}

void
tree(vector<vector<int>> l, vector<vector<int>> &xianglin, vector<vector<int>> &guanlian, vector<unsigned int> &bian) {
    for (int i = 1; i < 1 << l.size(); i++) {
        bian.clear();
        int n = 0;
        unsigned int x = i, place = 0;
        while (x) {
            if (x & 0x1) {
                bian.push_back(place);
                n++;
            }
            x >>= 1;
            place++;
        }
        if (n == l[0].size() - 1) {
            // 去除第一行判断矩阵是否满秩
            vector<vector<int>> matrix;
            for (auto j: bian) {
                vector<int> t;
                for (int k = 1; k < l[j].size(); k++) {
                    t.push_back(l[j][k]);
                }
                matrix.push_back(t);
            }
            if (Det(matrix) != 0) break;
        }
    }
    // 计算关联矩阵
    for (auto x: bian) {
        guanlian.push_back(l[x]);
    }
    for (int i = 0; i < l[0].size(); i++) {
        vector<int> t;
        t.assign(l[0].size(), 0);
        xianglin.push_back(t);
    }
    // 计算相邻矩阵
    for (auto i: guanlian) {
        vector<int> e;
        for (int j = 0; j < i.size(); j++) {
            if (i[j] == 1) e.push_back(j);
            if (e.size() == 2) break;
        }
        xianglin[e[0]][e[1]] = 1;
        xianglin[e[1]][e[0]] = 1;
    }
}

struct Node {
    Node *parent;
    int num;
};

vector<unsigned int> bfs_loop(const vector<vector<int>> &tree, int start, int end) {
    vector<bool> visited;
    visited.assign(tree.size(), false);
    visited[start] = true;
    vector<Node> points;
    for (int i = 0; i < tree.size(); i++) {
        Node t{nullptr, i};
        points.push_back(t);
    }
    queue<int> q;
    q.push(start);
    while (!q.empty()) {
        int now = q.front();
        q.pop();
        for (int i = 0; i < tree.size(); i++) {
            if (tree[now][i] == 1 && !visited[i]) {
                points[i].parent = &points[now];
                q.push(i);
                visited[i] = true;
            }
        }
        if (now == end) break;
    }
    vector<unsigned int> road;
    road.push_back(end);
    while (points[end].parent) {
        end = points[end].parent->num;
        road.insert(road.begin(), end);
    }
    return road;
}

vector<vector<int>> loop(const vector<vector<int>> &xianglin, vector<vector<int>> guanlian, vector<unsigned int> bian) {
    vector<unsigned int> xian;
    for (int i = 0; i < guanlian.size(); i++) {
        if (!count(bian.begin(), bian.end(), i)) {
            xian.push_back(i);
        }
    }
    vector<vector<unsigned int>> points;
    for (auto x: xian) {
        vector<unsigned int> e;
        for (int i = 0; i < guanlian[0].size(); i++) {
            if (guanlian[x][i] == 1) {
                e.push_back(i);
            }
        }
        vector<unsigned int> t = bfs_loop(xianglin, e[0], e[1]);
        t.push_back(e[0]);
        points.push_back(t);
    }
    vector<vector<int>> result;
    for (auto x: points) {
        int n = 1;
        vector<int> t;
        while (n < x.size()) {
            vector<int> m;
            m.assign(guanlian[0].size(), 0);
            m[x[n - 1]] = 1;
            m[x[n]] = 1;
            for (int i = 0; i < guanlian.size(); i++) {
                if (guanlian[i] == m) {
                    t.push_back(i);
                    break;
                }
            }
            n++;
        }
        result.push_back(t);
    }
    return result;
}

bool liantong(vector<vector<int>> matrix) {
    vector<bool> visited;
    visited.assign(matrix.size(), false);
    visited[0] = true;
    queue<int> q;
    q.push(0);
    while (!q.empty()) {
        int now = q.front();
        q.pop();
        for (int i = 0; i < matrix.size(); i++) {
            if (matrix[now][i] == 1 && !visited[i]) {
                q.push(i);
                visited[i] = true;
            }
        }
    }
    for (auto x: visited) {
        if (!x) return false;
    }
    return true;
}

vector<vector<int>>
geji(vector<vector<int>> xianglin, vector<vector<int>> guanlian, vector<unsigned int> bian) {
    vector<unsigned int> xian;
    for (int i = 0; i < guanlian.size(); i++) {
        if (!count(bian.begin(), bian.end(), i)) {
            xian.push_back(i);
        }
    }
    vector<vector<int>> result;
    for (auto x: bian) {
        vector<vector<int>> t(xianglin.begin(), xianglin.end());
        vector<int> e;
        for (int i = 0; i < guanlian[0].size(); i++) {
            if (guanlian[x][i] == 1) {
                e.push_back(i);
            }
        }
        t[e[0]][e[1]] = 0;
        t[e[1]][e[0]] = 0;
        vector<int> edge;
        edge.push_back(x);
        for (auto y: xian) {
            // 添加一条弦
            e.clear();
            for (int i = 0; i < guanlian[0].size(); i++) {
                if (guanlian[y][i] == 1) {
                    e.push_back(i);
                }
            }
            t[e[0]][e[1]] = 1;
            t[e[1]][e[0]] = 1;
            if (liantong(t)) {
                edge.push_back(y);
                t[e[0]][e[1]] = 0;
                t[e[1]][e[0]] = 0;
            }
        }
        result.push_back(edge);
    }
    return result;
}

vector<vector<int>> space(const vector<vector<int>> &circles) {
    vector<unsigned int> selected;
    vector<vector<int>> result;
    for (int i = 1; i < 1 << circles.size(); i++) {
        selected.clear();
        unsigned int x = i, place = 0;
        while (x) {
            if (x & 0x1) {
                selected.push_back(place);
            }
            x >>= 1;
            place++;
        }
        vector<int> t(circles[selected[0]].begin(), circles[selected[0]].end());
        selected.erase(selected.begin());
        for (auto e: selected) {
            for (auto each: circles[e]) {
                if (count(t.begin(), t.end(), each)) {
                    for (auto it = t.begin(); it != t.end();) {
                        if (*it == each) {
                            it = t.erase(it);
                        } else {
                            it++;
                        }
                    }
                } else {
                    t.push_back(each);
                }
            }
        }
        result.push_back(t);
    }
    return result;
}

int main() {
    int n, t;
    cout << "请输入点的个数:" << endl;
    cin >> n;
    cout << "请输入矩阵" << endl;
    vector<vector<int>> m;
    for (int i = 0; i < n; i++) {
        vector<int> temp;
        for (int j = 0; j < n; j++) {
            cin >> t;
            temp.push_back(t);
        }
        m.push_back(temp);
    }
    vector<vector<int>> g = guanlianMatrix(m);
    cout << "关联矩阵为：" << endl << "   ";
    for (int i = 0; i < g.size(); i++) {
        cout << "e" << i << "\t";
    }
    cout << endl;
    for (int i = 0; i < g[0].size(); i++) {
        cout << "v" << i << "  ";
        for (auto &j: g) {
            cout << j[i] << "\t";
        }
        cout << endl;
    }
    cout << "共有" << treeNum(m) << "颗树" << endl;
    vector<vector<int>> xianglin, guanlian;
    vector<unsigned int> bian;
    tree(g, xianglin, guanlian, bian);
    cout << "生成树的相邻矩阵为：" << endl << "   ";
    for (int i = 0; i < xianglin.size(); i++) {
        cout << "v" << i << "\t";
    }
    cout << endl;
    for (int i = 0; i < xianglin[0].size(); i++) {
        cout << "v" << i << "  ";
        for (auto &j: xianglin) {
            cout << j[i] << "\t";
        }
        cout << endl;
    }
    cout << "生成树关联矩阵为：" << endl << "   ";
    for (auto x: bian) {
        cout << "e" << x << "\t";
    }
    cout << endl;
    for (int i = 0; i < guanlian[0].size(); i++) {
        cout << "v" << i << "  ";
        for (auto &j: guanlian) {
            cout << j[i] << "\t";
        }
        cout << endl;
    }
    cout << "基本回路系统为：" << endl << "{ ";
    vector<vector<int>> circle = loop(xianglin, g, bian);
    for (int i = 0; i < circle.size(); i++) {
        for (int j = 0; j < circle[i].size(); j++) {
            cout << "e" << circle[i][j];
            if (j == circle[0].size() - 1 && i != circle.size() - 1) cout << ", ";
        }
    }
    cout << " }" << endl;

    vector<vector<int>> huanlu = space(circle);
    cout << "环路空间为：" << endl << "{ Φ ,";
    for (int i = 0; i < huanlu.size(); i++) {
        for (int j = 0; j < huanlu[0].size(); j++) {
            cout << "e" << huanlu[i][j];
            if (j == huanlu[0].size() - 1 && i != huanlu.size() - 1) cout << ", ";
        }
    }
    cout << " }" << endl;

    cout << "基本割集系统为：" << endl << "{ ";
    vector<vector<int>> gj = geji(xianglin, g, bian);
    for (int i = 0; i < gj.size(); i++) {
        cout << "{ ";
        for (int j = 0; j < gj[i].size(); j++) {
            if (j == gj[i].size() - 1) {
                cout << "e" << gj[i][j] << " } ";
                if (i != gj.size() - 1) cout << ",";
            } else {
                cout << "e" << gj[i][j] << ",";
            }
        }
    }
    cout << " }" << endl;

    cout << "断集空间为：" << endl << "{ Φ ,";
    vector<vector<int>> dj = space(gj);
    for (int i = 0; i < dj.size(); i++) {
        cout << "{ ";
        for (int j = 0; j < dj[i].size(); j++) {
            if (j == dj[i].size() - 1) {
                cout << "e" << dj[i][j] << " } ";
                if (i != dj.size() - 1) cout << ",";
            } else {
                cout << "e" << dj[i][j] << ",";
            }
        }
    }
    cout << " }" << endl;
    system("pause");
    return 0;
}

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