func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxn = 200000 + 10;   int num[maxn], ans;   void Solve() {     int n;     scanf( %d , &n);     for (int i = 1; i <= n; i++) scanf( %d , num + i);     sort(num + 1, num + 1 + n);     int nn = unique(num + 1, num + 1 + n) - (num + 1);     for (int i = 1; i <= nn; i++) {       int j = num[i] << 1;       int pos = lower_bound(num + 1, num + 1 + nn, j) - num;       while (num[pos - 1] < j && pos <= nn) {         ans = max(ans, num[pos - 1] % num[i]);         pos = lower_bound(num + pos + 1, num + 1 + nn, j) - num;         j += num[i];       }       ans = max(ans, num[pos - 1] % num[i]);     }     printf( %d , ans);   }   int main() {     Solve();     getchar();     getchar();     return 0;   }   