Easy-to-understand Three-Way-Partition inspired by 3-way-quickSort

```
public class Solution {
public void sortColors(int[] nums) {
int l = 0,r = nums.length-1,i=0;
while(i<=r){
if(nums[i]==0){swap(i++,l++,nums);}
else if(nums[i]==2){swap(i,r--,nums);}
else i++;
}
}
private void swap(int i, int j, int[] nums){
if(i==j)return;
nums[i]^=nums[j];
nums[j]^=nums[i];
nums[i]^=nums[j];
}
}
```