这题数据确实水，只需要比较上一周，但是刷题嘛，还是考虑全面比较好，优先队列实现的AC代码如下

#include<iostream>
#include<algorithm>
#include<string>
#include<cstring>
#include<map>
#include<vector>
#include<queue>
#include<cmath>
#include<cstdio>
#include<set>
#include<bitset>
#include<stack>

#define MAX_WEEK 10010

using namespace std;

int N, S;
long long allcost=0;

struct node
{
	int cost, submit, produce; 
	friend bool operator<(node a, node b)
		{return a.cost > b.cost;}
}cows[MAX_WEEK];

int main()
{
	scanf("%d%d", &N, &S);
	for(int i=0; i<N; i++)
	        scanf("%d%d", &cows[i].cost, &cows[i].submit);
	priority_queue<node> que;
	allcost += cows[0].submit * cows[0].cost;
	cows[0].cost += S;
	que.push(cows[0]);
	for(int i=1; i<N; i++)
	{
		node temp = que.top();
		que.pop();
		if(cows[i].cost > temp.cost)
			allcost += 1ll * temp.cost * cows[i].submit;
		else
			allcost += 1ll * cows[i].cost * cows[i].submit;
		cows[i].cost += S;
		temp.cost += S;
		que.push(cows[i]);
		que.push(temp);
	}
	cout << allcost << endl;;
}