L. String Functions

#include <iostream>
#include<bits/stdc++.h>
#define ll long long
using namespace std;

int main() {
 int n,q;
 string s;
 cin>>n>>q;
 cin>>s;
 string qu;
  int x,y;
  int pos;
 while(q--)
 {
     cin>>qu;
     if(qu == "pop_back")
     {
         s.pop_back();
     }
     else if( qu =="front ")
     {
         cout<<s.front()<<endl;
     }
     else if(qu =="back")
     {
         cout<<s.back()<<endl;

     }
     else if (qu =="sort")
     {
         cin>>x>>y;
         sort(s.begin() + min (x,y)-1 , s.begin() + max (x,y) );
     }
     else if("reverse")
     {
         cin>>x>>y;
         reverse(s.begin() + min (x,y)-1 , s.begin() + max (x,y) -1 );
     }
     else if("print")
     {
         cin>>pos;
         cout<<s[pos-1]<<endl;
     }
     else if ("substr")
     {
         cin>>x>>y;
         for(int i =min(x,y)-1 ;i<max(x,y)-1 ;i++)
         {
             cout<<s[i];
         }
         cout<<endl;
     }
     else
     {
         char m;
         cin>>m;
         s.push_back(m);
     }
 }

    return 0;
}