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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. #define pb push_back
  5. #define all(a) begin(a),end(a)
  6. using vi = vector<int>;
  7. using ll = long long;
  8.  
  9. const int mxN = (int)1e5;
  10. const int B = 300;
  11.  
  12. vi v;
  13. string s;
  14. int n, q; 
  15. ll sum, ans[mxN];
  16. int l[mxN], r[mxN], a[mxN], cnt[1<<26];
  17.  
  18. void add(int i){
  19.     for(auto u : v) sum+=cnt[a[i]^u];
  20.     cnt[a[i]]++;
  21. }
  22.  
  23. void rem(int i){
  24.     cnt[a[i]]--;
  25.     for(auto u : v) sum-=cnt[a[i]^u];
  26. }
  27.  
  28. int main(){
  29.     ios_base::sync_with_stdio(false); cin.tie(0);
  30.     cin >> n >> q >> s;
  31.     for(int i = 0; i < n; i++)
  32.         a[i+1]=a[i]^(1<<(s[i]-'a'));
  33.     v.pb(0); 
  34.     for(int i = 0; i < 26; i++) v.pb(1<<i);
  35.     for(int i = 0; i < q; i++) 
  36.         cin >> l[i] >> r[i], l[i]--;
  37.     vi ord(q,0); iota(all(ord),0);
  38.     sort(all(ord),[&](int i, int j){
  39.         if(l[i]/B!=l[j]/B) return l[i]<l[j];
  40.         return (l[i]/B)%2?r[i]>r[j]:r[i]<r[j];
  41.     });
  42.     int L = 0, R = -1;
  43.     for(auto i : ord){
  44.         while(L>l[i]) add(--L);
  45.         while(R<r[i]) add(++R);
  46.         while(L<l[i]) rem(L++);
  47.         while(R>r[i]) rem(R--);
  48.         ans[i] = sum;
  49.     }
  50.     for(int i = 0; i < q; i++) cout << ans[i] << "\n";
  51. }
Success #stdin #stdout 0.01s 5284KB
comments (?)
stdin
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10 2
lpdrbbrdpl
9 10
4 9
stdout
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2
11
https://ideone.com/x3j5jF
Palindrome substr queries
language:
C++14 (gcc 8.3)
created:
3 days ago
visibility:
public

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