Sort Colors - https://leetcode.com/problems/sort-colors/description/

gistfile1.txt

class Solution {
    public void sortColors(int[] nums) {
      // nums value is 0, 1, 2
      
      int left = 0;
      int right = nums.length-1 ;
      
      int i = 0;
      
      // move 0s and 2s so 1s will settle by themselves
      while (i < nums.length && i <= right && left < nums.length) {
        // If i is 0 then move it to left.
        if (nums[i] == 0) {
          swap(i, left, nums);
          left++;
          i++;
        } else if (nums[i] == 2) {
          swap(i, right, nums);
          right--;
        } else {
          i++;
        }
      }
        
    }
  
    private void swap(int i, int j, int[] nums) {
      //System.out.println("Swap " + i + " with " + j);
      int tmp = nums[i];
      nums[i] = nums[j];
      nums[j] = tmp;
    }
}