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  1. #include <bits/stdc++.h>
  2. #define FIN "aib.in"
  3. #define FOUT "aib.out"
  4.  
  5. using namespace std;
  6.  
  7. int N, M, fen[ 100005 ];
  8.  
  9. void update(int x, int val) {
  10.  
  11.      for( ;x<=N; x+=x^(x-1)&x) {
  12.  
  13.           fen[x] += val;
  14.      }
  15. }
  16.  
  17. int query(int x) {
  18.  
  19.     int ans;
  20.  
  21.     for(ans = 0; x; x-=x^(x-1)&x) {
  22.  
  23.         ans += fen[x];
  24.     }
  25.     return ans;
  26. }
  27.  
  28. int search(int x) {
  29.  
  30.     int log, index;
  31.  
  32.     for(log = 1; log < N; log <<= 1);
  33.  
  34.     for(index = 0; log; log>>=1) {
  35.  
  36.         if(index+log<=N && fen[index+log]<=x)
  37.  
  38.            index += log, x-=fen[index];
  39.     }
  40.  
  41.     return (!x ? index : -1);
  42. }
  43.  
  44. int main(void)
  45. {
  46.     int i, v, tip, a, b;
  47.  
  48.     //freopen(FIN, "r", stdin);
  49.     //freopen(FOUT, "w", stdout);
  50.  
  51.     scanf("%d %d", &N, &M);
  52.  
  53.     for(int i = 1; i <= N; ++i) {
  54.         cin>>v;
  55.         update(i,v);
  56.     }
  57.  
  58.     for( ; M; M--) {
  59.  
  60.       cin>>tip;
  61.  
  62.       if(tip == 0) {
  63.  
  64.         cin>>a>>b;
  65.         update(a,b);
  66.  
  67.       } else if(tip == 1) {
  68.  
  69.         cin>>a>>b;
  70.  
  71.         cout<<query(b)-query(a-1)<<endl;
  72.  
  73.       } else if(tip == 2) {
  74.  
  75.         cin>>a;
  76.  
  77.         printf("%d\n", (!a ? -1 : search(a)));
  78.       }
  79.     }
  80. }
Success #stdin #stdout 0.01s 5476KB
comments (?)
stdin 
8 6
25 42 8 15 1 55 16 67
0 5 12
2 25
2 90
1 7 7
1 2 8
2 241
stdout 
1
4
16
216
8
https://ideone.com/5Rlvmp
Fenwick Advanced Tree Data Structure
language:
C++ (gcc 8.3)
created:
2 years ago
visibility:
secret

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