443-string-compression.cpp

class Solution {
public:
    int compress(vector<char>& chars) {
        int i = 0, ansIndex = 0;
        int n = chars.size();
        while(i<n){
            int j = i+1;
            while(j<n && chars[i] == chars[j]) j+=1;
            
            
            // ya toh vector pura traverse krr diyaa
            // ya fir new/Different character encounter kia hai
            
            chars[ansIndex++] = chars[i];
            int count = j-i;
            if(count > 1){
                // converting counting into single digit and saving in answer
                string cnt = to_string(count);
                for(char ch: cnt) chars[ansIndex++] = ch;
                
            }
            i = j;
        }
        return ansIndex;
    }
};