LightOJ-1079-Just another Robbery(概率, 背包)

链接:

https://vjudge.net/problem/LightOJ-1079#author=feng990608

题意:

As Harry Potter series is over, Harry has no job. Since he wants to make quick money, (he wants everything quick!) so he decided to rob banks. He wants to make a calculated risk, and grab as much money as possible. But his friends - Hermione and Ron have decided upon a tolerable probability P of getting caught. They feel that he is safe enough if the banks he robs together give a probability less than P.

思路:

概率,把小于最大值,变成大于最小概率,用背包搞一下就行,之前刷背包刷到过,现在居然忘了..

代码:

#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
//#include <memory.h>
#include <queue>
#include <set>
#include <map>
#include <algorithm>
#include <math.h>
#include <stack>
#include <string>
#include <assert.h>
#include <iomanip>
#define MINF 0x3f3f3f3f
using namespace std;
typedef long long LL;

double Dp[100010], P[110];
int M[110];
int n;

int main()
{
    int t, cnt = 0;
    scanf("%d", &t);
    while (t--)
    {
        memset(Dp, 0, sizeof(Dp));
        double p;
        int sum = 0;
        scanf("%lf%d", &p, &n);
        for (int i = 1;i <= n;i++)
            scanf("%d%lf", &M[i], &P[i]), sum += M[i];
        p = 1-p;
        Dp[0] = 1.0;
        for (int i = 1;i <= n;i++)
        {
            for (int j = sum;j >= M[i];j--)
                Dp[j] = max(Dp[j], Dp[j-M[i]]*(1-P[i]));
        }
        int res = 0;
        for (int i = sum;i >= 0;i--)
            if (Dp[i] >= p)
            {
                res = i;
                break;
            }
        printf("Case %d: %d\n", ++cnt, res);
    }

    return 0;
}