Count Subarrays with Equal 0, 1 and 2 | OA | MUST DO

https://practice.geeksforgeeks.org/problems/equal-0-1-and-23208/1?page=1&difficulty[]=1&difficulty[]=2&status[]=unsolved&status[]=attempted&category[]=Strings&sortBy=submissions

Given a string str of length N which consists of only 0, 1 or 2s, count the number of substring which have equal number of 0s, 1s and 2s.

Example 1:

Input: str = “0102010”
Output: 2
Explanation: Substring str[2, 4] = “102” and
substring str[4, 6] = “201” has equal number
of 0, 1 and 2
Example 2:

Input: str = “11100022”
Output: 0
Explanation: There is no substring with
equal number of 0 , 1 and 2.

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class Solution{
public:
long long getSubstringWithEqual012(string str) {
        long long count =0;
        map<pair<long long,long long>,long long>mp;
        long long ones =0;
        long long zeros =0;
        long long twos =0;
        mp[{0,0}]=1;

        for(int i=0; i<str.length();i++){
            if(str[i]=='1'){
                ones++;
            }
            if(str[i]=='2'){
                twos++;
            }
            if(str[i]=='0'){
                zeros++;
            }
            pair<int,int>p = {zeros-ones,zeros-twos};
            mp[p]++;
        }
        return count;
    }
};