> #include <iostream>
> #include <stdio.h>
> #include <queue>
> using namespace std;
> 
> const int THRES = 200;
> 
> const int SSS = 2147483647;
> const int TTT = -2147483648;
> int N, M;
> int graph[THRES][THRES] = {{0}};
> bool s[THRES] = {0}, t[THRES] = {0};//false表示可用
> 
> void init(){
> 	for(int i = 0; i < THRES; i++){
> 		for(int j = 0; j < THRES; j++){
> 			graph[i][j] = 0;
> 		}
> 	}
> 	for(int i = 0; i < THRES; i++) s[i]=t[i]=0;
> }
> 
> bool pushflow(){
> 	//如果push不了，返回false
> 	queue<int> bfs;
> 	bool getT = false;
> 	int noT;
> 	int S[THRES] = {0}, T[THRES] = {0};
> 	for(int i = 1; i < N; i++){
> 		if(!s[i]){
> 			S[i] = SSS;
> 			bfs.push(i);
> 		}
> 	}
> 	while(!bfs.empty()){
> 		int cur = bfs.front();
> 		bfs.pop();
> 		if(cur > 0){
> 			//是s这边的点
> 			for(int j = 1; j <= M; j++){
> 				if(graph[cur][j] == 1 && T[j] == 0){
> 					bfs.push(-j);
> 					T[j] = cur;
> 				}
> 			}
> 		}
> 		else{
> 			//是t这边的点
> 			int j = -cur;
> 			if(!t[j]){
> 				getT = true;
> 				noT = cur;
> 				break;
> 			}
> 			for(int i = 1; i < N; i++){
> 				if(graph[i][j] == -1 && S[i] == 0){
> 					bfs.push(i);
> 					S[i] = cur;
> 				}
> 			}
> 		}
> 	}
> 	if(!getT) return false;
> 	t[-noT] = true;
> 	int TtoS = 1;
> 	while(1){
> 		if(TtoS){
> 			//push路径当前从S端到T端
> 			int noS = T[-noT];
> 			graph[noS][-noT] = -1;
> 			noT = noS;
> 		}
> 		else{
> 			//从T端到S端
> 			int noS = S[noT];
> 			if(noS == SSS){
> 				s[noT] = true;
> 				break;
> 			}
> 			graph[noT][-noS] = 1;
> 			noT = noS;
> 		}
> 		TtoS = 1 - TtoS;
> 	}
> 	return true;
> }
> 
> 
> int main() {
> 	int t;
> 	scanf("%d", &t);
> 	for(int ii = 0; ii < t; ii++){
> 		init();
> 		int str;
> 		scanf("%d%d", &N, &str);
> 		N++;
> 		M=N-1;
> 		for(int i = 0; i < str; i++){
> 			int a,b;
> 			scanf("%d%d", &a, &b);
> 			graph[a][b] = 1;
> 		}
> 		int cnt = 0;
> 		while(pushflow()){
> 			cnt++;
> 		}
> 		printf("%d\n", M-cnt);
> 	}
> 	return 0;
> }
最小路径覆盖模板。。。