暑期dp46道(34)--HDOJ 1203 01背包

题目链接：HDOJ 1203

题解：01背包问题，注意至少拿到一个offer的概率 b：一个offer拿不到的概率a,则b=1-a;

所以

dp[j] = Max(dp[j], 1-(1- dp[j - c[i]])*(1 - w[i]));

代码：

#include<cstdio>#include<cstring>#include<string>#define debug 0#define M(a) memset(a,0,sizeof(a))#define Max(a,b) ((a>b)?a:b)#define REP(o) for(int i=1;i<=o;i++)const int maxn = 10000 + 5;int n, m;int c[maxn]; double w[maxn], dp[maxn];void Do(){for (int i = 1; i <= n; i++)for (int j = m; j >= c[i]; j--){dp[j] = Max(dp[j], 1 - (1 - dp[j - c[i]])*(1 - w[i]));}printf("%.1f%%\n", 100 * dp[m]);}int main(){#if debugfreopen("in.txt", "r", stdin);#endif//debugwhile (~scanf("%d%d", &m, &n)){if (n == 0 && m == 0)break;M(dp);REP(n){scanf("%d%lf", &c[i], &w[i]);}Do();}return 0;}