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

排序以后枚举尾部。尺取，头部单调，维护一下就好。

排序O(nlogn),枚举O(n)

#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;
}