HDU-1203 I NEED A OFFER!

 1 #include<iostream>
 2 #include<algorithm>
 3 #include<cstring>
 4 #include<iomanip>
 5 #define mem(a) memset(a, 0, sizeof(a))
 6 using namespace std;
 7 const int maxn = 10050;
 8 double dp[maxn];
 9 double value[maxn]; int cost[maxn];
10 int main()
11 {
12    int v, n;
13     while(cin >> v >> n && (v || n)) {
14         for(int i = 1 ; i <= n ; i++)
15             cin >> cost[i] >> value[i];
16         mem(dp);
17         for(int i = 1 ; i <= n ; i++)
18             for(int j = v ; j >= cost[i] ; j--)
19                 dp[j] = max(dp[j], 1 - ((1 - dp[j - cost[i]]) * (1 - value[i])));
20         cout << setiosflags(ios::fixed) << setprecision(1) << 100 * dp[v] << "%" << endl;
21     }
22     return 0;
23 }