hdu2955 dp

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#include <cstdio>#include <iostream>#include <algorithm>#include <queue>#include <cmath>#include <cstring>#include <stack>#include <set>#include <map>#include <vector>using namespace std;#define INF 0x2fffffff#define LL long long#define MAX(a,b) ((a)>(b))?(a):(b)#define MIN(a,b) ((a)<(b))?(a):(b)int l[1000];double w[1000];double dp[10005][105];int main(){    int t;    cin >> t;    double a;    int n;    while(t--){        scanf("%lf %d",&a,&n);        int sum  = 0;        for(int i = 1;i <= n;i++){            scanf("%d%lf",&l[i],&w[i]);            w[i] = 1 -w[i];            sum += l[i];        }        for(int i = 0;i <= sum;i++){            for(int j = 0;j <= n;j++){                dp[i][j] = 0;            }        }        dp[0][0] = 1;        for(int i = 0;i <= sum;i++){            for(int j = 1;j <= n;j++){                if(l[j] > i){                    dp[i][j] = dp[i][j-1];                }                else{                    dp[i][j] = max(dp[i][j-1],dp[i-l[j]][j-1]*w[j]);                }            }        }        int ans = 0;        a = 1 - a;        for(int i = 0;i <= sum;i++){            if(dp[i][n] >= a ){                ans = i;            }        }        printf("%d\n",ans);    }    return 0;}

同样是01背包问题，但是这道题变换了一个，这里面的价值现在变成了实数，所以这时候要改变dp的策略

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