given an array that contains no duplicate value, and a target value, search the insert position this target should be.

it’s just a regular binary search.

class Solution {
  public int searchInsert(int[] nums, int target) {
    int left = 0, right = nums.length - 1;
    while (left <= right) {
      int mid = left + (right - left) / 2;
      if (nums[mid] == target) return mid;
      if (target < nums[mid]) right = mid - 1;
      else left = mid + 1;
    }
    return left; //left will stopped at the first one which large than target
  }
}

but what if the given array contains duplicate value?