以下两个版本的代码都是错的。。。

#include <iostream>
#include <cstring>
using namespace std;
#define maxn 30

int v, lea[maxn];
int g, inc[maxn][maxn];
int cho[maxn], q = 0, vis[maxn];
int ans[maxn], p = maxn;

bool check() {
	printf("\n# Run Function: check()\n");
	bool able = true;
	int sum[maxn];
	memset(sum, 0, sizeof(sum));
	for(int i = 1; i <= q; i ++)
		for(int j = 1; j <= v; j ++)
			sum[j] += inc[i][j];
	printf("inc:\n");
	for(int i = 1; i <= q; i ++) {
		printf("food #%d includes:", i);
		for(int j = 1; j <= v; j ++)
			printf("%d ", inc[i][j]);
		printf("\n");
	}
	printf("\nsum:");
	for(int i = 1; i <= v; i ++)
		cout << sum[i] << " ";
	cout << endl;
	for(int i = 1; i <= v; i ++)
		if(sum[i] < lea[i])
			able = false, printf("Error: i = %d\n", i);
	printf("# End Function: return %d\n", able);
	return able;
}

void dfs(int k) {
	printf("\n# Run Function:dfs(%d)\n", k);
	if(k > g) {
		if(!check())
			return;
		if(p > q) {
			p = q;
			for(int i = 1; i <= q; i ++)
				ans[i] = cho[i];
			printf("// data changed: p = %d\n", p);
			for(int i = 1; i <= p; i ++)
				printf("%d ", ans[i]);
			cout << endl;
		}
		return;
	}
	for(int i = k; i <= g; i ++)
		if(!vis[i]) {
			vis[i] = 1,q ++, ans[q] = i;
			dfs(i);
			vis[i] = 0, q --, ans[q + 1] = 0;
		}
	printf("\n# End Function:dfs(%d)\n", k);
}

int main() {
	cin >> v;
	for(int i = 1; i <= v; i ++)
		cin >> lea[i];
	cin >> g;
	for(int i = 1; i <= g; i ++)
		for(int j = 1; j <= v; j ++)
			cin >> inc[i][j];
	dfs(1);
	cout << p;
	for(int i = 1; i <= p; i ++)
		cout << " " <<ans[i];
	return 0;
}

#include <iostream>
#include <cstring>
using namespace std;
#define maxn 30

int v, lea[maxn];
int g, inc[maxn][maxn];
int cho[maxn], q = 0, vis[maxn];
int ans[maxn], p = maxn;

bool check() {
	printf("\n# Run Function: check()\n");
	bool able = true;
	int sum[maxn];
	memset(sum, 0, sizeof(sum));
	for(int i = 1; i <= q; i ++)
		for(int j = 1; j <= v; j ++)
			sum[j] += inc[i][j];
	printf("inc:\n");
	for(int i = 1; i <= q; i ++) {
		printf("food #%d includes:", i);
		for(int j = 1; j <= v; j ++)
			printf("%d ", inc[i][j]);
		printf("\n");
	}
	printf("\nsum:");
	for(int i = 1; i <= v; i ++)
		cout << sum[i] << " ";
	cout << endl;
	for(int i = 1; i <= v; i ++)
		if(sum[i] < lea[i])
			able = false, printf("Error: i = %d\n", i);
	printf("# End Function: return %d\n", able);
	return able;
}

void dfs(int k) {
	printf("\n# Run Function:dfs(%d)\n", k);
	if(k > g) {
		if(!check())
			return;
		if(p > q) {
			p = q;
			for(int i = 1; i <= q; i ++)
				ans[i] = cho[i];
			printf("// data changed: p = %d\n", p);
			for(int i = 1; i <= p; i ++)
				printf("%d ", ans[i]);
			cout << endl;
		}
		return;
	}
	for(int i = k + 1; i <= g; i ++) {
		q ++, ans[q] = i;
		dfs(i);
		ans[q] = 0, q --;
		dfs(i);
	}
	printf("\n# End Function:dfs(%d)\n", k);
}

int main() {
	cin >> v;
	for(int i = 1; i <= v; i ++)
		cin >> lea[i];
	cin >> g;
	for(int i = 1; i <= g; i ++)
		for(int j = 1; j <= v; j ++)
			cin >> inc[i][j];
	dfs(1);
	cout << p;
	for(int i = 1; i <= p; i ++)
		cout << " " <<ans[i];
	return 0;
}