loj2256 「SNOI2017」英雄联盟

真的是裸背包啊……

#include <iostream>
#include <cstdio>
using namespace std;
typedef long long ll;
int n, k[125], c[125], sum[125];
ll m, dp[125][240795];
int main(){
    cin>>n>>m;
    for(int i=1; i<=n; i++)
        scanf("%d", &k[i]);
    for(int i=1; i<=n; i++){
        scanf("%d", &c[i]);
        sum[i] = sum[i-1] + k[i] * c[i];
    }
    dp[0][0] = 1;
    for(int i=1; i<=n; i++)
        for(int j=0; j<=sum[i]; j++){
            dp[i][j] = dp[i-1][j];
            for(int l=1; l<=k[i]; l++)
                if(j-l*c[i]>=0){
                    ll tmp;
                    if((double)dp[i-1][j-l*c[i]]*l>=m)  tmp = m;
                    else    tmp = dp[i-1][j-l*c[i]] * l;
                    dp[i][j] = max(dp[i][j], tmp);
                }
        }
    for(int i=0; i<=sum[n]; i++)
        if(dp[n][i]==m){
            printf("%d\n", i);
            return 0;
        }
    return 0;
}