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Author: kedebug

SearchforaRange/SearchforaRange.cpp

@@ -0,0 +1,44 @@
+class Solution {
+public:
+    vector<int> searchRange(int A[], int n, int target) {
+        // Start typing your C/C++ solution below
+        // DO NOT write int main() function
+        
+        vector<int> range;
+        range.push_back(find_lower_bound(A, n, target));
+        range.push_back(find_upper_bound(A, n, target));
+        return range;
+    }
+    
+    int find_lower_bound(int A[], int n, int target) {
+        int left = 0, right = n - 1;
+        while (left <= right) {
+            int mid = left + (right - left) / 2;
+            if (A[mid] >= target) {
+                right = mid - 1;
+            }
+            else {
+                left = mid + 1;
+            }
+        }
+        if (A[left] == target)
+            return left;
+        return -1;
+    }
+    
+    int find_upper_bound(int A[], int n, int target) {
+        int left = 0, right = n - 1;
+        while (left <= right) {
+            int mid = left + (right - left) / 2;
+            if (A[mid] <= target) {
+                left = mid + 1;
+            }
+            else {
+                right = mid - 1;
+            }
+        }
+        if (A[right] == target)
+            return right;
+        return -1;
+    }
+};