LeetCode: Search for a Range

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 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 };

 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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