HDU 5961 (bitset)

题意：给出两个图，他们的并是竞赛图。判断这两图是不是同时是传递的。

直接忽略竞赛图的性质暴力bitset。

#include <bits/stdc++.h>
#define Clear(x,y) memset (x,y,sizeof(x))
#define FOR(a,b,c) for (int a = b; a <= c; a++)
#define REP(a,b,c) for (int a = b; a >= c; a--)
#define fi first
#define se second
#define pii pair<int, int>
#define pli pair<long long, int>
#define pb push_back
#define mod 1000000007
using namespace std;
#define maxn 2022
#define maxm maxn*maxn

struct node {
    int v, next;
}edge[maxm];
int head[maxn], cnt;
int n;
char mp[maxn][maxn];
bitset <maxn> b[maxn];

void add_edge (int u, int v) {
    edge[cnt].v = v, edge[cnt].next = head[u]; head[u] = cnt++;
    b[u][v] = 1;
}

bool legal (char ch) {
    memset (head, -1, sizeof head);
    cnt = 0;
    for (int i = 1; i <= n; i++) b[i].reset ();
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= n; j++) if (mp[i][j] == ch) {
            add_edge (i, j);
        }
    }
    for (int i = 1; i <= n; i++) {
        for (int j = head[i]; j+1; j = edge[j].next) {
            int v = edge[j].v;
            if ((b[i]&b[v]) != b[v]) return 0;
        }
    }
    return 1;
}

int main () {
    //freopen ("more.in", "r", stdin);
    int t; scanf ("%d", &t);
    while (t--) {
        scanf ("%d", &n);
        for (int i = 1; i <= n; i++) {
            scanf ("%s", mp[i]+1);
        }
        if (legal ('P') && legal ('Q')) {
            printf ("T\n");
        }
        else
            printf ("N\n");
    }
    return 0;
}