func_code_string: #include <bits/stdc++.h>   using namespace std;   int a[500010];   pair<int, int> b[500010];   int c[500010];   int T, n, tot;   int main(void) {     T = 1;     while (T--) {       scanf( %d , &n);       for (int i = 1; i <= n; ++i) {         scanf( %d , &a[i]);         b[i] = {a[i], -i};       }       sort(b + 1, b + 1 + n);       for (int i = 1; i <= n; ++i) {         if (-b[i].second >= b[i].first) {           int x = -(b[i].second + b[i].first);           int pos = upper_bound(c + 1, c + 1 + tot, x) - c;           c[pos] = x;           tot = max(pos, tot);         }       }       printf( %d n , tot);     }     return 0;   }   