HDOJ -1203 I NEED A OFFER!

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这道题用dp(i)表示用完i万元得不到一个off的最小概率,状态转移方程： dp[j] = min(dp[j], dp[j-sch[i].a] * sch[i].b);

#include<cstdio>#include<cstdlib>#include<cstring>#include<algorithm>#include<cmath>#include<queue>#include<vector>#include <iostream>#include <sstream>using namespace std;#define INF 1e8struct School{    int a;    double b;}sch[10005];double dp[10005];int main(){  //  freopen("in.txt", "r", stdin);    int n, m;    while(cin >> n >> m)    {        if(n == 0 && m == 0)            break;        for(int i = 0; i < m; i++)        {            cin >> sch[i].a >> sch[i].b;            sch[i].b = 1.0 - sch[i].b;        }        for(int i = 0; i <= n; i++)            dp[i] = INF;        dp[0] = 1.0;        for(int i = 0; i < m; i++)            for(int j = n; j >= sch[i].a; j--)                if(dp[j - sch[i].a] == INF)                  continue;                else                 dp[j] = min(dp[j], dp[j-sch[i].a] * sch[i].b);        double mins = 1.0;        for(int i = n; i >= 0; i--)           mins = min(mins, dp[i]);        printf("%.1f%%\n", (1.0 - mins) * 100);    }    return 0;}

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