add mock problems

- google oa 202005160200
- facebook phone 202005160237

Author: zhuli19901106

mock/facbook-phone-202005160237/1.docx

@@ -0,0 +1,12 @@
+import re
+
+class Solution:
+    def isPalindrome(self, s: str) -> bool:
+        s = re.sub('[^a-z0-9]', '', s.lower())
+        n = len(s)
+        i = 0
+        while i < n - 1 - i:
+            if s[i] != s[n - 1 - i]:
+                return False
+            i += 1
+        return True

mock/facbook-phone-202005160237/1.pdf

@@ -0,0 +1,20 @@
+class Solution:
+    def validPalindrome(self, s: str) -> bool:
+        def isPal(s, i, j):
+            while i < j:
+                if s[i] != s[j]:
+                    return False, i, j
+                i += 1
+                j -= 1
+            return True, -1, -1
+
+        ret, i, j = isPal(s, 0, len(s) - 1)
+        if ret:
+            return True
+        ret, _, _ = isPal(s, i + 1, j)
+        if ret:
+            return True
+        ret, _, _ = isPal(s, i, j - 1)
+        if ret:
+            return True
+        return False

mock/facbook-phone-202005160237/1_AC.py

@@ -0,0 +1,34 @@
+class Solution:
+    def addOperators(self, num: str, target: int) -> List[str]:
+        if len(num) == 0:
+            return []
+
+        ops = {}
+        ops['+'] = lambda x, y: x + y
+        ops['-'] = lambda x, y: x - y
+        ops['*'] = lambda x, y: x * y
+
+        res = []
+        def dfs(idx, arr, op):
+            nonlocal res
+
+            if idx == len(num):
+                expr = ''.join(arr)
+                n = eval(expr)
+                if n == target:
+                    res.append(expr)
+                return
+            if op:
+                for c in ops:
+                    arr.append(c)
+                    dfs(idx, arr, not op)
+                    arr.pop()
+            else:
+                nr = len(num) if num[idx] != '0' else idx + 1
+                for i in range(idx, nr):
+                    x = num[idx: i + 1]
+                    arr.append(x)
+                    dfs(i + 1, arr, not op)
+                    arr.pop()
+        dfs(0, [], False)
+        return res