Author: Vinay Kushwaha
Tester: Ujjawal Gupta
You are given a string and you have to choose two characters at index i and j such that i<j and s[i]=s[j]. and remove these characters .You can perform this operation any number of time .You have to telll if you can empty the string by performing the opration.
If you observe the question carefully you can see that you can always empty the string if it appears even number of times . So we store the frequency of each character in a map and check if alll the characters appeared even number of times or not.