【DP】 HDOJ 3357 Stock Chase

#include <iostream>  
#include <queue>  
#include <stack>  
#include <map>  
#include <set>  
#include <bitset>  
#include <cstdio>  
#include <algorithm>  
#include <cstring>  
#include <climits>  
#include <cstdlib>
#include <cmath>
#include <time.h>
#define maxn 305
#define maxm 10005
#define eps 1e-10
#define mod 998244353
#define INF 999999999
#define lowbit(x) (x&(-x))
#define mp mark_pair
#define ls o<<1
#define rs o<<1 | 1
#define lson o<<1, L, mid  
#define rson o<<1 | 1, mid+1, R  
typedef long long LL;
//typedef int LL;
using namespace std;
LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}
void scanf(int &__x){__x=0;char __ch=getchar();while(__ch==' '||__ch=='
')__ch=getchar();while(__ch>='0'&&__ch<='9')__x=__x*10+__ch-'0',__ch = getchar();}
// head

int mat[maxn][maxn];
int n, m;
void init(void)
{
    memset(mat, 0, sizeof mat);
}
void work(int _)
{
    int ans = 0, a, b;
	for(int i = 1; i <= n; i++) mat[i][i] = 1;
    while(m--) {
        //scanf("%d%d", &a, &b);
		scanf(a), scanf(b);
        if(mat[b][a]) ans++;
        else if(!mat[a][b]){
            mat[a][b] = 1;
            for(int i = 1; i <= n; i++)
				if(mat[i][a])
					for(int j = 1; j <= n; j++)
						if(mat[b][j])
							mat[i][j] = 1;
        }
    }
    printf("%d. %d
", _, ans);
}
int main(void)
{
    int _ = 0;
    while(scanf("%d%d", &n, &m), n!=0 || m!=0) {
        init();
        work(++_);
    }
    return 0;
}