2.5.3 二分图判定

#include "pch.h"
#include <iostream>
#include <algorithm>
#include <queue>
#include <set>
#include <vector>

using namespace std;

const int maxn = 1000;
vector<int> G[maxn];
int V;
int color[maxn];

bool dfs(int v, int c) {
	color[v] = c;
	for (int i = 0; i < V; i++) {
		if (color[G[i][v]] == c){
			return false;
		}
		else if (color[G[i][v]] == 0 && !dfs(G[i][v], -c)) {
			return false;
		}
	}
	return true;
}

void solve() {
	for (int i = 0; i < V; i++) {
		if (color[i] == 0) {
			if (!dfs(i, 1)) {
				printf("no");
			}
		}
	}
	printf("yes");
}