public class Solution {
     /**
 * @param nums: An integer array sorted in ascending order
 * @param target: An integer
 * @return an integer
 */
public int findPosition(int[] nums, int target) {
    // Write your code here
    if (nums == null) return -1;
    int length = nums.length;
    int start = 0;
    int end = length - 1;
    while (start + 1 < end) {
        int mid = start + (end - start) / 2;
        if (nums[mid] == target) return mid;
        else if (nums[mid] < target) start = mid;
        else end = mid;
    }
    return -1;
}
}