Educational Codeforces Round 44 (Rated for Div. 2)+E. Pencils and Boxes+树状数组

 1 #include<bits/stdc++.h>
 2 #include <iostream>
 3 #include <string.h>
 4 #include <algorithm>
 5 #include <stdio.h>
 6 #include <math.h>
 7 #define ll long long
 8 #define pb push_back
 9 using namespace std;
10 const int N=800010;
11 const int INF=1<<30;
12 const int inf=0x3f3f3f3f;
13 const int maxn=5e5+10;
14 const int mod=1e9+7;
15 int n,k,d;
16 int lowbit(int x)
17 {
18     return x&(-x);
19 }
20 int a[maxn],b[maxn];
21 bool v[maxn];
22 int add(int x)
23 {
24     while(x<=n+1)
25     {
26         b[x]++;x+=lowbit(x);
27     }
28 }
29 int get(int x)
30 {
31     int ans=0;
32     while(x>0)
33     {
34         ans+=b[x];x-=lowbit(x);
35     }
36     return ans;
37 }
38 int main()
39 {
40     scanf("%d %d %d ",&n,&k,&d);
41     for(int i=1;i<=n;i++)
42     {
43         scanf("%d",&a[i]);
44     }
45     sort(a+1,a+1+n);
46     add(n+1);
47     for(int i=n-k+1;i>=1;i--)
48     {
49         int pos=upper_bound(a+1,a+1+n,a[i]+d)-a;
50         if(pos>=i+k-1&&get(pos)-get(i+k-1)>0)
51         {
52             v[i]=true;add(i);
53         }
54     }
55     if(v[1])printf("YES\n");
56     else printf("NO\n");
57     return 0;
58 }