Added search range

Author: shichao-an

search_for_a_range/solution.py

@@ -0,0 +1,26 @@
+class Solution:
+    # @param A, a list of integers
+    # @param target, an integer to be searched
+    # @return a list of length 2, [index1, index2]
+    def searchRange(self, A, target):
+        res = [-1, -1]
+        n = len(A)
+        l = 0
+        r = n - 1
+        while l <= r:
+            mid = l + (r - l) // 2
+            if target == A[mid]:
+                res = [mid, mid]
+                p = q = mid
+                while p >= 0 and A[p] == target:
+                    res[0] = p
+                    p -= 1
+                while q <= n - 1 and A[q] == target:
+                    res[1] = q
+                    q += 1
+                break
+            elif target < A[mid]:
+                r -= 1
+            else:
+                l += 1
+        return res