Leetcode34. 在排序数组中查找元素的第一个和最后一个位置

题目地址: ​​https://leetcode.cn/problems/find-first-and-last-position-of-element-in-sorted-array/submissions/​​

运行的效果：

代码如下:

public static int[] searchRange(int[] nums, int target) {
        int[] result = {-1, -1};
        if (nums.length == 1) {
            if (nums[0] == target) {
                result[0] = 0;
                result[1] = 0;
                return result;
            } else {
                return result;
            }
        }
        int left = 0, right = nums.length - 1;
        while (left < right) {
            if (right - left == 1) {  //两个指针挨到一起了
                if (nums[left] == target) {
                    result[0] = left;
                }
                if (nums[right] == target) {
                    result[1] = right;
                }
                if (result[0] == -1) {
                    result[0] = result[1];
                }
                if (result[1] == -1) {
                    result[1] = result[0];
                }
                return result;
            }
            int mid = (left + right) / 2 > 0 ? (left + right) / 2 : 1;
            if (nums[mid] > target) {
                right = mid;
            }
            if (nums[mid] < target) {
                left = mid;
            }
            if (nums[mid] == target) {
                left = mid - 1;
                right = mid + 1;
                while (left >= 0 && nums[left] == target) {
                    left--;
                }
                while (right < nums.length && nums[right] == target) {
                    right++;
                }
                result[0] = left + 1;
                result[1] = right - 1;
                break;
            }
        }
        return result;
    }