USACO2.1.4 Healthy Holsteins (holstein)

枚举每一个饲料的选择方案，选出符合条件的，然后挑出最小的方案。

用一个二进制数来表示选的方案。

/*

ID:shijiey1

PROG:holstein

LANG:C++

*/

#include <cstdio>

#include <cstring>

#include <algorithm>

#include <vector>

using namespace std;

struct Ans{

int cnt;

int arr[30];

Ans() {

cnt = 0;

memset(arr, 0, sizeof(arr));

}

bool operator < (const Ans &a) const {

if (cnt != a.cnt) return cnt < a.cnt;

for (int i = 0; i < cnt; i++) {

if (arr[i] != a.arr[i]) {

return arr[i] < a.arr[i];

}

}

return 1;

}

};

int n, m;

int arr[30];

int feed[30][30];

int ans[30];

vector<Ans> re;

void success(int bit) {

for (int i = 0; i < n; i++) {

if (ans[i] < arr[i]) {

return;

}

}

Ans a = Ans();

int step = 1;

while (bit) {

if (bit & 1) {

a.arr[a.cnt++] = step;

}

bit >>= 1;

step++;

}

re.push_back(a);

}

void solve() {

for (int bit = 1; bit < (1 << m); bit++) {

int t = bit;

int step = 0;

memset(ans, 0, sizeof(ans));

while (t) {

if (t & 1) {

for (int i = 0; i < n; i++) {

ans[i] += feed[step][i];

}

}

t >>= 1;

step++;

}

success(bit);

}

}

int main() {

freopen("holstein.in", "r", stdin);

freopen("holstein.out", "w", stdout);

scanf("%d", &n);

for (int i = 0; i < n; i++) {

scanf("%d", &arr[i]);

}

scanf("%d", &m);

for (int i = 0; i < m; i++) {

for (int j = 0; j < n; j++) {

scanf("%d", &feed[i][j]);

}

}

solve();

sort(re.begin(), re.end());

printf("%d", re[0].cnt);

for (int i = 0; i < re[0].cnt; i++) {

printf(" %d", re[0].arr[i]);

}

printf("\n");

return 0;

}