日记2.17(1)

1. 枚举二分图
   Color Graph
   题目让给无向图边刷红色，不允许奇环全红，相当于删除边，使得图中只有偶环，只有偶环即2分图，看题目数据范围容易推得是枚举题。
   于是这一题就是枚举二分图左边的点
   code:来自某大佬的博客：https://www.cnblogs.com/ucprer/p/11931263.html

#include <bits/stdc++.h>
using namespace std;
const int maxn = 105;
const int maxm = 1e4 + 5;
struct edge
{
    int u, v;
} E[maxm];
int tot = 0;
void addedge(int u, int v)
{
    E[++tot].u = u;
    E[tot].v = v;
}
int color[maxn];
int main()
{
    int T;
    cin >> T;
    for(int kase = 1; kase <= T; kase++)
    {
        int n, m;
        scanf("%d%d", &n, &m);
        fill(color, color + 1 + n, 0);
        tot = 0;
        for(int i = 1; i <= m; i++)
        {
            int u, v;
            scanf("%d%d", &u, &v);
            addedge(u, v);
        }
        int ans = 0;
        for(int meijv = 0; meijv <= (1 << n) - 1; meijv++)
        {
            int mj = meijv;
            for(int i = 1; i <= n; i++)
            {
                if(mj & 1)
                {
                    color[i] = 1;
                }
                else color[i] = 0;
                mj >>= 1;
            }
            int res = 0;
            for(int i = 1; i <= tot; i++)
            {
                if(color[E[i].u] != color[E[i].v])
                {
                    res++;
                }
            }
            ans = max(ans, res);
        }
        printf("Case #%d: %d\n", kase, ans);
    }
}

来源：CSDN

作者：妖怪无面男

链接：https://blog.csdn.net/qq_40192591/article/details/104355682