class Solution {

public int compress(char[] chars) {

if(chars.length == 0) return -1;

int start = 0;

for(int end = 0, count = 0; end < chars.length; end++) {

count++;

if(end == chars.length-1 || chars[end] != chars[end + 1] ) {

//We have found a difference or we are at the end of array

chars[start] = chars[end]; // Update the character at start pointer

start++;

if(count != 1) {

// Copy over the character count to the array

char[] arr = String.valueOf(count).toCharArray();

for(int i=0;i<arr.length;i++, start++)

chars[start] = arr[i];

}

// Reset the counter

count = 0;

}

}

return start;

}

}