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;
}