01背包问题，设f[i]为拿了i件能得到的最大价值。关于限制条件Q只要在每次更新f[i]的值的时候都判断当前值是否是小于Q的最大值即可
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int maxn = 31;
double f[maxn],val[400];
int main() {
int N; double Q;
while(scanf("%lf%d",&Q,&N),N) {
memset(f,0,sizeof(f));
double ans = 0;
for(int i = 0;i < N;i++) {
int n,pos = 0; scanf("%d",&n);
double sum[3] = {0,0,0};
for(int j = 0;j < n;j++) {
char kind; double _val;
scanf(" %c:%lf",&kind,&_val);
if(kind < ‘A‘ || kind > ‘C‘) sum[0] = 1005;
else {
sum[kind - ‘A‘] += _val;
if(sum[kind - ‘A‘] > 600) sum[0] = 1005;
}
if(sum[0] + sum[1] + sum[2] > 1000) continue;
val[pos++] = _val;
}
if(sum[0] + sum[1] +sum[2] > 1000) continue;
for(int j = N;j >= 1;j--) {
f[j] = max(f[j],f[j - 1] + sum[0] + sum[1] + sum[2]);
if(f[j] > ans && f[j] <= Q) ans = f[j];
}
}
printf("%.2f\n",ans);
}
return 0;
}