Count Number of Homogenous Substrings.cpp

// Runtime: 84 ms (Top 7.54%) | Memory: 11.8 MB (Top 13.97%)
class Solution {
public:
    int countHomogenous(string s) {

        int n = s.length();
        long long count = 0;
        long long len = 0;
        int MOD = 1000000007;

        int i = 0;
        while(i<n)
        {
            len = 1;

            // get length of same char substring
            while(i+1<n && s[i]==s[i+1])i++,len++;

            // calculate number of substring from same char substring and then sum
            count = (count + ((len * (len+1)) /2 )%MOD ) % MOD;

            i++;
        }

        return count;
    }
};