uva 1508 - Equipment(暴力+枚举子集)

题目链接：uva 1508 - Equipment

题目大意：给出n个5元组，要求从中选取k个，要求5个位置上的数的最大值的和尽量大。

解题思路：对于每个元组，有25−1种选取方法，那么处理出这些选取方法中的最大值即可，然后暴力枚举。

#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;
const int maxn = 10005;
const int maxm = 5;
const int maxs = (1<<5)-1;
const int INF = 0x3f3f3f3f;

int N, K;
int num[maxn][maxm+5], rec[maxs+5];

void cal (int a[maxm+5]) {

    for (int s = 0; s <= maxs; s++) {
        int tmp = 0;
        for (int j = 0; j < maxm; j++)
            if (s&(1<<j))
                tmp += a[j];
        rec[s] = max(rec[s], tmp);
    }
}

void init () {
    scanf("%d%d", &N, &K);
    K = min(K, maxm);
    memset(rec, 0, sizeof(rec));

    for (int i = 0; i < N; i++) {
        for (int j = 0; j < maxm; j++)
            scanf("%d", &num[i][j]);
        cal(num[i]);
    }
}

int dfs (int d, int S) {
    if (d == K)
        return S ? -INF : 0;

    if (S == 0)
        return -INF;

    int ans = 0;
    for (int s0 = S; s0; s0 = (s0-1)&S)
        ans = max(ans, dfs(d+1, s0^S) + rec[s0]);
    return ans;
}

int main () {
    int cas;
    scanf("%d", &cas);
    while (cas--) {
        init();
        printf("%d\n", dfs(0, maxs));
    }
    return 0;
}