LeetCode: Search for a Range

一次过

 1 class Solution {

 2 public:

 3     vector<int> searchRange(int A[], int n, int target) {

 4         // Start typing your C/C++ solution below

 5         // DO NOT write int main() function

 6         int left = 0;

 7         int right = n-1;

 8         while (left <= right) {

 9             int mid = (left+right)/2;

10             if (target == A[mid]) {

11                 int l, r;

12                 l = r = 0;

13                 while (A[mid] == A[mid-l]) l++;

14                 while (A[mid] == A[mid+r]) r++;

15                 vector<int> ret;

16                 ret.push_back(mid-l+1);

17                 ret.push_back(mid+r-1);

18                 return ret;

19             }

20             if (target > A[mid]) left = mid+1;

21             else right = mid-1;

22         }

23         return {-1, -1};

24     }

25 };

 C#

 1 public class Solution {

 2     public int[] SearchRange(int[] nums, int target) {

 3         int left = 0;

 4         int right = nums.Length - 1;

 5         int[] ans = new int[2];

 6         while (left <= right) {

 7             int mid = (left + right) / 2;

 8             if (target == nums[mid]) {

 9                 int l = 0, r = 0;

10                 while (mid - l >= 0 && nums[mid] == nums[mid-l]) l++;

11                 while (mid + r < nums.Length && nums[mid] == nums[mid+r]) r++;

12                 ans[0] = mid - l + 1;

13                 ans[1] = mid + r - 1;

14                 return ans;

15             }

16             if (target > nums[mid]) left = mid + 1;

17             else right = mid - 1;

18         }

19         ans[0] = ans[1] = -1;

20         return ans;

21     }

22 }

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