HDU 1281——棋盘游戏——————【最大匹配、枚举删点、邻接表方式】

#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<iostream>
using namespace std;
const int maxn = 110;
struct Edge{
    int from, to, dist, next;
    Edge(){}
    Edge(int _from,int _to,int _next):from(_from),to(_to),next(_next){}
}edges[maxn*maxn*3];    //direction
struct Point{
    int x,y;
}points[maxn*maxn];
int tot , head[maxn];
int linker[3*maxn], used[3*maxn], c[maxn];
void init(){
    tot = 0;
    memset(head,-1,sizeof(head));
}
void AddEdge(int _u,int _v){
    edges[tot] = Edge(_u,_v,head[_u]);
    head[_u] = tot++;
}
bool dfs(int u,int _n,int _del){
    for(int e = head[u]; e != -1; e = edges[e].next){
        int v = edges[e].to;
        if(u == points[_del].x && v == points[_del].y) continue;
        if(!used[v]){
            used[v] = u;
            if(linker[v] == -1 || dfs(linker[v],_n,_del)){
                linker[v] = u;
                return true;
            }
        }
    }
    return false;
}
int hungary(int p, int n,int del){
    int ret = 0;
    memset(linker,-1,sizeof(linker));
    for(int i = 1; i <= p; i++){
        memset(used,0,sizeof(used));
        if(dfs(i,n,del))
            ret++;
    }
    return ret;
}
int main(){
    int n, m, T, p, k, cas = 0;
    while(scanf("%d%d%d",&n,&m,&k)!=EOF){
        int a,b;
        init();
        for(int i = 1; i <= k; i++){
            scanf("%d%d",&a,&b);
            AddEdge(a,b);
        }
        int ans = hungary(n,m,0);
        int cc = 1;
        for(int i = 1; i <= m; i++){
            if(linker[i] != -1){
                points[cc].x = linker[i];
                points[cc].y = i;
                cc++;
            }
        }
        int tmp, num = 0;
        for(int i = 1; i < cc; i++){
            tmp = hungary(n,m,i);
            if(tmp != ans){
                num++;
            }
        }
        printf("Board %d have %d important blanks for %d chessmen.\n",++cas,num,ans);
    }
    return 0;
}