LeetCode34-34. 在排序数组中查找元素的第一个和最后一个位置

🔗:代码随想录:二分查找的算法讲解:有关left<=right和left<right的区别

class Solution {public int[] searchRange(int[] nums, int target) {int n=nums.length;int l=0,h=n-1;if(nums==null){return null;    }if(n==0){return new int[]{-1,-1};    }if(target<nums[0]||target>nums[n-1]){return new int[]{-1,-1}; }int m=(l+h)/2;boolean Find=false;while(l<=h){m=(l+h)/2;if(nums[m]<target){l=m+1;}else if(nums[m]>target){h=m-1;}else{Find=true;break;}}if(nums[m]==target&&Find){int i=m,j=m;while(i>0&&nums[i]==target&&nums[i-1]==nums[i]){i--;}while(j+1<n&&nums[j]==target&&nums[j+1]==nums[j]){j++;}return new int[]{i,j};}return new int[]{-1,-1};    }}