func_code_string: #include <bits/stdc++.h>   using namespace std;   int input[100000];   int output[100000];   pair<pair<int, int>, int> queries[100000];   int blockSize;   bool mo_compare(pair<pair<int, int>, int>& x, pair<pair<int, int>, int>& y) {     int firstBlockIndex = x.first.first / blockSize;     int secondBlockIndex = y.first.first / blockSize;     if (firstBlockIndex == secondBlockIndex) {       return x.first.second < y.first.second;     }     return firstBlockIndex < secondBlockIndex;   }   void inline removeElement(unordered_map<int, int>& lookup, int val,                             int& result) {     unordered_map<int, int>::iterator itr = lookup.find(val);     if (itr != lookup.end()) {       if (itr->first == itr->second) {         result--;       }       itr->second--;       if (itr->first == itr->second) {         result++;       }     } else {       lookup[val]--;     }   }   void inline addElement(unordered_map<int, int>& lookup, int val, int& result) {     unordered_map<int, int>::iterator itr = lookup.find(val);     if (itr != lookup.end()) {       if (itr->first == itr->second) {         result--;       }       itr->second++;       if (itr->first == itr->second) {         result++;       }     } else {       lookup[val]++;       if (val == 1) {         result++;       }     }   }   int main() {     cin.tie(NULL);     int n, m;     cin >> n >> m;     blockSize = static_cast<int>(sqrt(n));     for (int i = 0; i < n; i++) {       cin >> input[i];     }     for (int i = 0; i < m; i++) {       pair<pair<int, int>, int>& query = queries[i];       cin >> query.first.first >> query.first.second;       query.first.first--;       query.first.second--;       query.second = i;     }     sort(queries, queries + m, mo_compare);     unordered_map<int, int> lookup;     int result = 0;     int prev_l = 0, prev_r = -1, left, right, index;     unordered_map<int, int>::iterator itr;     for (int i = 0; i < m; i++) {       left = queries[i].first.first;       right = queries[i].first.second;       index = queries[i].second;       while (left > prev_l) {         removeElement(lookup, input[prev_l], result);         prev_l++;       }       while (left < prev_l) {         prev_l--;         addElement(lookup, input[prev_l], result);       }       while (right < prev_r) {         removeElement(lookup, input[prev_r], result);         prev_r--;       }       while (right > prev_r) {         prev_r++;         addElement(lookup, input[prev_r], result);       }       output[index] = result;     }     for (int i = 0; i < m; i++) {       cout << output[i] <<   n ;     }     return 0;   }   