思路

暴力

 public int[] searchRange(int[] nums, int target) {
        int[] targetNums = {-1,-1};
     //找到初始位置
        for(int i=0;i<nums.length;i++){
            if(nums[i]==target){
                targetNums[0]=i;
                break;
            }
        }
     //如果没有找到 则返回-1
        if(targetNums[0]==-1)
            return targetNums;
     //找到结束位置
        for(int i=nums.length-1;i>=targetNums[0];i--){
            if(nums[i]==target){
                targetNums[1]=i;
                break;
            }
        }
        return targetNums;
    }

二分

class Solution {
    public int[] searchRange(int[] nums, int target) {
        int start = Solution.firstGreaterEqual(nums, target);
        if(start==nums.length||nums[start]!=target)
            return new int[]{-1,-1};
        return new int[]{start,Solution.firstGreaterEqual(nums, target+1)-1};
    }

    private static int firstGreaterEqual(int[] A,int target){
        int low = 0,high=A.length;
        while(low<high){
            int mid = low+((high-low)>>1);
            if(A[mid]<target)
                low=mid+1;
            else
                high=mid;
        }
        return low;
    }
}