【LG3231】[HNOI2013]消毒

题面

洛谷

题解

代码

(100pts)

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring> 
#include<cmath> 
#include<algorithm>
using namespace std;
inline int gi() {
	register int data = 0, w = 1;
	register char ch = 0;
	while (!isdigit(ch) && ch != '-') ch = getchar();
	if (ch == '-') w = -1, ch = getchar();
	while (isdigit(ch)) data = 10 * data + ch - '0', ch = getchar();
	return data * w; 
}
#define MAX_N 5005 
struct Graph { int to, next; } e[MAX_N * 10]; int fir[MAX_N], e_cnt;
void clearGraph() { memset(fir, -1, sizeof(fir)); e_cnt = 0; }
void Add_Edge(int u, int v) { e[e_cnt] = (Graph){v, fir[u]}; fir[u] = e_cnt++; }
int A, B, C; 
int tot, xx[MAX_N], yy[MAX_N], zz[MAX_N];
int vis[MAX_N], dep, match[MAX_N];
bool dfs(int x) {
    for (int i = fir[x]; ~i; i = e[i].next) {
        int v = e[i].to;
        if (dep != vis[v]) {
            vis[v] = dep;
            if (!match[v] || dfs(match[v])) {
                match[v] = x; 
                return true;
            }
        }
    }
    return false;
}
int main() {
	int T = gi();
	int a, b, c, pos; 
	while (T--) {
		tot = 0; 
		a = gi(), b = gi(), c = gi(), pos = 1;
		if (b < a && b < c) pos = 2; else if (c < a && c < b) pos = 3;
		for (int i = 1; i <= a; i++)
			for (int j = 1; j <= b; j++)
				for (int k = 1; k <= c; k++) { 
					int x = gi(); 
					if (!x) continue; 
					else if (pos==1) ++tot, zz[tot]=i, xx[tot] = j, yy[tot] = k; 
                    else if (pos==2) ++tot, zz[tot]=j, xx[tot] = i, yy[tot] = k; 
                    else if (pos==3) ++tot, zz[tot]=k, xx[tot] = j, yy[tot] = i; 
				}
		A = a, B = b, C = c;
		if (pos == 2) swap(A, B); 
        if (pos == 3) swap(A, C);
		int ans = 1e9; 
		for (int i = 0, sum; i < (1 << A); i++) {
			for (int j = 1; j <= B; j++) match[j] = 0, fir[j] = -1;
			e_cnt = 0; 
			sum = A;
			for (int j = i; j; j -= (j & -j)) --sum;
			for (int j = 1; j <= tot; j++)
				if ((1 << (zz[j] - 1)) & i) Add_Edge(xx[j], yy[j]); 
	    	for (int j = 1; j <= B; j++) {
		    	++dep;
		    	if (dfs(j)) ++sum;
		    	if (sum >= ans) break; 
		    } 
		    ans = min(ans, sum); 
		}
		printf("%d
", ans); 
	} 
	return 0; 
}