Codeforces Round #321 (Div. 2) B. Kefa and Company （尺取）

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
//#define LOCAL
const int maxn = 1e5+5;
struct Node
{
int m,s;
void IN(){ scanf("%d%d",&m,&s); }
bool operator < (const Node&rh) const {
return m < rh.m;
}
}nd[maxn];

ll ss[maxn];

int main()
{
#ifdef LOCAL
freopen("in.txt","r",stdin);
#endif
int n,d; scanf("%d%d",&n,&d);
for(int i = 1; i <= n; i++){
nd[i].IN();
}
sort(nd+1,nd+1+n);
for(int i = 1; i <= n; i++){
ss[i] = ss[i-1]+nd[i].s;
}
ll ans = 0;
for(int i = 1,j = 1; i <= n; i++){
while(j<n && nd[j+1].m - nd[i].m < d) j++;
ans = max(ans,ss[j]-ss[i-1]);
}
printf("%I64d",ans);
return 0;
}