hdu 1203 I NEED A OFFER! dp

设dp【i】为花费i，一个offer都没收到的最小概率，跑一下01背包最后1-dp【m】即可

#include <bits/stdc++.h>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <cmath>
#include <time.h>
#include <vector>
#include <cstdio>
#include <string>
#include <iomanip>
///cout << fixed << setprecision(13) << (double) x << endl;
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

#define lson l, mid, rt << 1
#define rson mid + 1, r, rt << 1 | 1
#define ls rt << 1
#define rs rt << 1 | 1
#define pi acos(-1.0)
#define eps 1e-8
#define Mp(a, b) make_pair(a, b)
#define asd puts("asdasdasdasdasdf");
typedef long long ll;
//typedef __int64 LL;
const int inf = 0x3f3f3f3f;
const int N = 10010;

int n, m;
double v[N];
int w[N];
double dp[N];

int main()
{
	while( ~scanf("%d%d", &m, &n) ) {
		if( m == n && m == 0 )
			break;
		for( int i = 1; i <= n; ++i ) {
			scanf("%d %lf", &w[i], &v[i]);
			v[i] = 1-v[i];
		}
		for( int i = 0; i <= m; ++i )
			dp[i] = 1.0;
		for( int i = 1; i <= n; ++i ) {
			for( int j = m; j >= w[i]; --j ) {
				dp[j] = min( dp[j], dp[j-w[i]] * v[i] );
			}
		}
		double ans = inf;
		for( int i = 0; i <= m; ++i ) {
			ans = min( ans, dp[i] );
		}
		printf("%.1f%%\n", ( 1-ans ) * 100);
	}
	return 0;
}