offer2-68

给定一个排序的整数数组 nums 和一个整数目标值 target ，请在数组中找到 target ，并返回其下标。如果目标值不存在于数组中，返回它将会被按顺序插入的位置。

请必须使用时间复杂度为 O(log n) 的算法。

示例 1:

输入: nums = [1,3,5,6], target = 5
输出: 2

示例 2:

输入: nums = [1,3,5,6], target = 2
输出: 1

示例 3:

输入: nums = [1,3,5,6], target = 7
输出: 4

示例 4:

输入: nums = [1,3,5,6], target = 0
输出: 0

示例 5:

输入: nums = [1], target = 0
输出: 0

提示:

• 1 <= nums.length <= 104
• -104 <= nums[i] <= 104
• nums 为无重复元素的升序排列数组
• -104 <= target <= 104

//leetcode submit region begin(Prohibit modification and deletion)
class Solution {

    public int searchInsert(int[] nums, int target) {
        int start = 0, end = nums.length - 1;

        while (start <= end) {
            if (start == end) {
                return nums[start] >= target ? start : start + 1;
            }

            if (start + 1 == end) {
                if (nums[start] >= target) {
                    return start;
                } else if (nums[end] >= target) {
                    return end;
                } else {
                    return end + 1;
                }
            }

            int mid = start + (end - start) / 2;

            if (nums[mid] == target) {
                return mid;
            } else if (nums[mid] < target) {
                start = mid;
            } else {
                end = mid;
            }
        }

        return -1;
    }
}
//leetcode submit region end(Prohibit modification and deletion)