奔小康赚大钱 HDU - 2255最大权值匹配 KM模板

​​传送门​​​ 思路：原来想用dfs做，然后果断wa Tle，后来才知道要用KM最大权值匹配，学习了。
AC代码：

#include<iostream>
#include<cstring>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<queue>
#include<cmath>
#include<cctype>
#include<stack>
#include<map>
#include<string>
#include<cstdlib>
#define min(a,b) a>b?b:a
#define max(a,b) a>b?a:b
#define mem(a, b) memset(a, b, sizeof(a))
using namespace std;
const int maxn = 400, INF = 0x7fffffff;
int usedx[maxn], usedy[maxn], w[maxn][maxn], bx[maxn], by[maxn], cx[maxn], cy[maxn];
int nx, ny, n, minn, max_value;
int dfs(int u)
{
    usedx[u] = 1;
    for(int i=1; i<=ny; i++)
    {
        if(usedy[i] == -1)
        {
            int t = bx[u] + by[i] - w[u][i];
            if(t == 0)
            {
                usedy[i] = 1;
                if(cy[i] == -1 || dfs(cy[i]))
                {
                    cy[i] = u;
                    cx[u] = i;
                    return 1;
                }
            }
            else if(t > 0)
                minn = min(minn, t);
        }
    }
    return 0;
}
int km()
{
    mem(cx, -1);
    mem(cy, -1);
    mem(bx, -1);
    mem(by, 0);
    for(int i=1; i<=nx; i++)
        for(int j=1; j<=ny; j++)
            bx[i] = max(bx[i], w[i][j]);
    for(int i=1; i<=nx; i++)
    {
        while(1)
        {
            minn = INF;
            mem(usedx, -1);
            mem(usedy, -1);
            if(dfs(i)) break;
            for(int j=1; j<=nx; j++)
                if(usedx[j] != -1) bx[j] -= minn;
            for(int j=1; j<=ny; j++)
                if(usedy[j] != -1) by[j] += minn;
        }
    }
    max_value = 0;
    for(int i=1; i<=nx; i++)
        if(cx[i] != -1)
            max_value += w[i][cx[i]];
    printf("%d\n",max_value);
    return 1;
}

int main()
{
    while(~scanf("%d",&n))
    {
        for(int i=1; i<=n; i++)
            for(int j=1; j<=n; j++)
                scanf("%d",&w[i][j]);
        nx = ny = n;
        km();
    }
    return 0;
}