CodeForces - 366C Dima and Salad （DP&01背包）

CodeForces - 366C Dima and Salad Time Limit: 1000MS   Memory Limit: 262144KB   64bit IO Format: %I64d & %I64u Submit Status Description Dima, Inna and Seryozha have gathered in a room. That's right, someone's got to go. To cheer Seryozha up and inspire him to have a walk, Inna decided to cook something. Dima and Seryozha have n fruits in the fridge. Each fruit has two parameters: the taste and the number of calories. Inna decided to make a fruit salad, so she wants to take some fruits from the fridge for it. Inna follows a certain principle as she chooses the fruits: the total taste to the total calories ratio of the chosen fruits must equal k. In other words,  , where aj is the taste of the j-th chosen fruit and bj is its calories. Inna hasn't chosen the fruits yet, she is thinking: what is the maximum taste of the chosen fruits if she strictly follows her principle? Help Inna solve this culinary problem — now the happiness of a young couple is in your hands! Inna loves Dima very much so she wants to make the salad from at least one fruit. Input The first line of the input contains two integers n, k(1 ≤ n ≤ 100, 1 ≤ k ≤ 10). The second line of the input contains nintegers a1, a2, ..., an(1 ≤ ai ≤ 100) — the fruits' tastes. The third line of the input contains n integers b1, b2, ..., bn(1 ≤ bi ≤ 100) — the fruits' calories. Fruit number i has taste ai and calories bi. Output If there is no way Inna can choose the fruits for the salad, print in the single line number -1. Otherwise, print a single integer — the maximum possible sum of the taste values of the chosen fruits. Sample Input Input 3 2 10 8 1 2 7 1 Output 18 Input 5 3 4 4 4 4 4 2 2 2 2 2 Output -1 Hint In the first test sample we can get the total taste of the fruits equal to 18 if we choose fruit number 1 and fruit number 2, then the total calories will equal 9. The condition  fulfills, that's exactly what Inna wants. In the second test sample we cannot choose the fruits so as to follow Inna's principle. //题意： 在一个水果篮里有n种水果，并且这些水果每一种都有一个美味度和一个卡路里的属性，  小明要从这些水果中选出来一些做一个水果沙拉， 并且要求他的水果沙拉的美味度是 卡路里的k倍，问小明是否可以做出这么一个水果沙拉，若不能输出-1， 否则输出复合要求的最大的美味值。 //思路： 转化一下就是一个01背包了，但要注意为了避免出现负数的情况，所以将值加上10000，可以避免  #include<stdio.h> #include<string.h> #include<algorithm> #include<iostream> #define INF 0x3f3f3f3f #define ull unsigned long long #define ll long long #define IN __int64 #define N 110 #define M 12000 using namespace std; struct zz { int a; int b; }p[N]; int dp[N][200010]; int main() { int n,k,i,j,x; while(scanf("%d%d",&n,&k)!=EOF) { for(i=1;i<=n;i++) scanf("%d",&p[i].a); for(i=1;i<=n;i++) scanf("%d",&x),p[i].b=x*k; memset(dp,-0x3f,sizeof(dp)); dp[0][10000]=0; for(i=1;i<=n;i++) { int w=p[i].a-p[i].b; for(j=M;j>=w;j--) { if(dp[i-1][j]<dp[i-1][j-w]+p[i].a) dp[i][j]=dp[i-1][j-w]+p[i].a; else dp[i][j]=dp[i-1][j]; } } if(dp[n][10000]) printf("%d\n",dp[n][10000]); else printf("-1\n"); } return 0; }