BZOJ1740: [Usaco2005 mar]Yogurt factory 奶酪工厂

 1 #include<stdio.h>
 2 #include<string.h>
 3 #include<stdlib.h>
 4 #include<algorithm>
 5 //#include<iostream>
 6 using namespace std;
 7 
 8 int n,m;
 9 #define maxn 10011
10 int a,b;
11 #define LL long long
12 int main()
13 {
14     scanf("%d%d",&n,&m);LL Min=1e15,ans=0;
15     for (int i=1;i<=n;i++)
16     {
17         scanf("%d%d",&a,&b);
18         a-i*m<Min && (Min=a-i*m);
19         ans+=(Min+i*m)*b;
20     }
21     printf("%lld\n",ans);
22     return 0;
23 }