34. 在排序数组中查找元素的第一个和最后一个位置

二分

class Solution {
    public int[] searchRange(int[] nums, int target) {
        int l = 0, r = nums.length - 1;

        while(l < r){
            int mid = l + r >> 1;
            if(nums[mid] >= target) r = mid;
            else l = mid + 1;
        }

        if(nums.length == 0 || nums[l] != target) return new int[]{-1, -1};
        int start = l;

        l = 0;
        r = nums.length - 1;
        while(l < r){
            int mid = l + r + 1 >> 1;
            if(nums[mid] > target) r = mid - 1;
            else l = mid;
        }

        return new int[]{start, l};
    }
}