public class Solution {
/**
* @param nums: The integer array you should partition
* @param k: An integer
* @return: The index after partition
*/
public int partitionArray(int[] nums, int k) {
if (nums == null) return 0;
int i = 0, j = nums.length - 1;
while (i <= j) {
while (i <= j && nums[i] < k) {
i++;
}
while (i <= j && nums[j] >= k) {
j--;
}
if (i <= j) {
int temp = nums[i];
nums[i++] = nums[j];
nums[j--] = temp;
}
}
return i;
}
}
