ms1797

/*
  Infix to postfix conversion in C++
  Input Postfix expression must be in a desired format.
  Operands and operator, both must be single character.
  Only '+'  ,  '-'  , '*', '/' and '^' (for exponentiation)  operators are expected.
*/
#include<iostream>
#include<stack>
#include<string>

ms1797

class Solution {
public:    
    string minWindow(string s, string t) {
        unordered_map<char, int> table;
        
        // initialize frequency table for t
        for(char c : t){
            table[c]++;
        }