func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MAXN = 100010;   bool vis[MAXN];   char str[MAXN];   int main() {     gets(str);     int len = strlen(str);     char maxch = 0;     memset(vis, false, sizeof(vis));     for (int i = len - 1; i >= 0; i--) {       if (str[i] >= maxch) vis[i] = true;       maxch = max(maxch, str[i]);     }     for (int i = 0; i < len; i++) {       if (vis[i]) putchar(str[i]);     }     puts(  );     return 0;   }   