有向图的传递闭包

参考：https://wenku.baidu.com/view/0fdb85062af90242a995e504.html

#include <bits/stdc++.h>
using namespace std;
const int v=4;
const int N=10;
bool g[N][N]={{0,1,0,0},{0,0,0,1},{0,0,0,0},{1,0,1,0}},temp[N][N];
void floyd()//三重循环找闭包
{
    for (int k=0;k<v;k++)//k为中间节点
    {
        for (int i=0;i<v;i++)
        {
            for (int j=0;j<v;j++)
            {
                temp[i][j]=g[i][j]||(g[i][k]&g[k][j]);
            }
        }
        for (int i=0;i<v;i++)//把temp矩阵复制到g矩阵
        {
            for (int j=0;j<v;j++)
            {
                g[i][j]=temp[i][j];
            }
        }
    }
    for (int i=0;i<v;i++)//输出
    {
        for (int j=0;j<v;j++)
        {
            printf("%2d ",temp[i][j]);
        }
        printf("\n");
    }
}
int main()
{
    cout<<"the number of vertex:\n"<<v<<endl;
    cout<<"the original array:\n";
    for (int i=0;i<v;i++)//输出原始矩阵
    {
        for (int j=0;j<v;j++)
        {
            printf("%2d ",g[i][j]);
        }
        printf("\n");
    }
    cout<<"the transitive closure:\n";
    memset(temp,0,sizeof(temp));
    floyd();

    return 0;
}