朋友圈

#include "stdafx.h"
#include <iostream>
#include <vector>
using namespace std;
void visit(vector<vector<int>>&, vector<bool>&, int);
int findCircleNum(vector<vector<int>>&);

int findCircleNum(vector<vector<int>>& M)
{
    int ans = 0;
    vector<bool> is_visit(M.size(), 0);
    //vector<vector<int>> list;
    for (int i = 0; i < M.size(); i++)
    {
        if (is_visit[i] == false)
        {
            visit(M, is_visit, i);
            ans++;
        }
    }
    return ans;
}

void visit(vector<vector<int>>& M,vector<bool>& is_visit, int v)
{
    is_visit[v] = 1;
    for (int i = 0; i < M.size(); i++)
    {
        if (M[v][i] == 1 && is_visit[i] == 0)
        {
            visit(M, is_visit, i);
        }
    }
}

int main()
{
    vector < vector < int >> in1 =
    { { 1, 1, 0 },
    { 1, 1, 0 },
    { 0, 0, 1 } };

    vector < vector < int >> in2 =
    { { 1, 1, 0 },
    { 1, 1, 1 },
    { 0, 1, 1 } };

    cout << "ans is:" << findCircleNum(in1) << endl;
    cout << "ans is:" << findCircleNum(in2) << endl;
    return 0;
}