[BZOJ1433][luogu_P2055][ZJOI2009]假期的宿舍

试题描述

输入

输出

输入示例

1

3

1 1 0

0 1 0

0 1 1

1 0 0

1 0 0

输出示例

^_^

数据规模及约定

对于 \(30\texttt{%}\) 的数据满足 \(1 \le n \le 12\)。

对于 \(100\texttt{%}\) 的数据满足 \(1 \le n \le 50,1 \le T \le 20\)。

题解

每个人和每个人的床分别建一个节点，源点向不回家的和不是学生的人连边，是学生的床向汇点连边，每个人向他认识人的床连边，以上所有边容量都为 \(1\)，跑最大流看是否满。

#include <iostream>

#include <cstdio>

#include <cstdlib>

#include <cstring>

#include <cctype>

#include <algorithm>

using namespace std;

#define rep(i, s, t) for(int i = (s); i <= (t); i++)

#define dwn(i, s, t) for(int i = (s); i >= (t); i--)

int read() {

	int x = 0, f = 1; char c = getchar();

	while(!isdigit(c)){ if(c == '-') f = -1; c = getchar(); }

	while(isdigit(c)){ x = x * 10 + c - '0'; c = getchar(); }

	return x * f;

}

#define maxn 110

#define maxm 5210

#define oo 2147483647

struct Edge {

	int from, to, flow;

	Edge() {}

	Edge(int _1, int _2, int _3): from(_1), to(_2), flow(_3) {}

};

struct Dinic {

	int n, m, s, t, head[maxn], nxt[maxm];

	Edge es[maxm];

	int vis[maxn], Q[maxn], hd, tl;

	int cur[maxn];

	void init() {

		m = 0; memset(head, -1, sizeof(head));

		return ;

	}

	void setn(int _) {

		n = _;

		return ;

	}

	void AddEdge(int a, int b, int c) {

		es[m] = Edge(a, b, c); nxt[m] = head[a]; head[a] = m++;

		es[m] = Edge(b, a, 0); nxt[m] = head[b]; head[b] = m++;

		return ;

	}

	bool BFS() {

		memset(vis, 0, sizeof(vis));

		vis[t] = 1;

		hd = tl = 0; Q[++tl] = t;

		while(hd < tl) {

			int u = Q[++hd];

			for(int i = head[u]; i != -1; i = nxt[i]) {

				Edge& e = es[i^1];

				if(!vis[e.from] && e.flow) {

					vis[e.from] = vis[u] + 1;

					Q[++tl] = e.from;

				}

			}

		}

		return vis[s] > 0;

	}

	int DFS(int u, int a) {

		if(u == t || !a) return a;

		int flow = 0, f;

		for(int& i = cur[u]; i != -1; i = nxt[i]) {

			Edge& e = es[i];

			if(vis[e.to] == vis[u] - 1 && (f = DFS(e.to, min(a, e.flow)))) {

				flow += f; a -= f;

				e.flow -= f; es[i^1].flow += f;

				if(!a) return flow;

			}

		}

		return flow;

	}

	int MaxFlow(int _s, int _t) {

		s = _s; t = _t;

		int flow = 0;

		while(BFS()) {

			rep(i, 1, n) cur[i] = head[i];

			flow += DFS(s, oo);

		}

		return flow;

	}

} sol;

bool stu[maxn];

int main() {

	int T = read();

	while(T--) {

		int n = read(), S = (n << 1) + 1, T = S + 1;

		sol.init(); sol.setn((n << 1) + 2);

		int cnt = 0;

		rep(i, 1, n){ stu[i] = read(); if(stu[i]) sol.AddEdge(i + n, T, 1); }

		rep(i, 1, n) if(!read() || !stu[i]) sol.AddEdge(S, i, 1), cnt++;

		rep(i, 1, n) rep(j, 1, n) if(read() || i == j) sol.AddEdge(i, j + n, 1);

		puts(sol.MaxFlow(S, T) == cnt ? "^_^" : "T_T");

	}

	return 0;

}