Merge branch 'master' of github.com:yanglbme/leetcode

Author: yanglbme

solution/014.Longest Common Prefix/Solution.py

@@ -0,0 +1,25 @@
+class Solution:
+    def longestCommonPrefix(self, strs):
+        """
+        :type strs: List[str]
+        :rtype: str
+        """
+        if strs == []:
+            return ''
+        if len(strs) == 1:
+            return strs[0]
+        strs.sort(key=lambda x : len(x))
+        flag=False
+        prefix=''
+        for j in range(1,len(strs[0])+1):
+            prefix=strs[0][:j]
+            for i in range(1,len(strs)):
+                if prefix == strs[i][:j]:
+                    flag=True
+                else:
+                    flag=False
+                if not flag:
+                    prefix0=prefix[:-1]
+                    return prefix0
+                    break
+        return prefix

solution/046.Permutations/Solution.py

@@ -0,0 +1,15 @@
+class Solution:
+    def permute(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: List[List[int]]
+        """
+        if len(nums) <= 1: 
+            return [nums]
+        ans = []
+        for i, num in enumerate(nums):
+            n = nums[:i] + nums[i+1:]
+            for y in self.permute(n):
+                ans.append([num] + y)
+        return ans
+        

solution/047.Permutations II/Solution.py

@@ -0,0 +1,40 @@
+class Solution:
+    def permuteUnique(self, nums):
+        ans = [[]]
+        for n in nums:
+            new_ans = []
+            for l in ans:
+                for i in range(len(l)+1):
+                    new_ans.append(l[:i]+[n]+l[i:])
+                    if i<len(l) and l[i]==n: break              #handles duplication
+            ans = new_ans
+        return ans
+
+class Solution:
+    def permute(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: List[List[int]]
+        """
+        if len(nums) <= 1: 
+            return [nums]
+        ans = []
+        for i, num in enumerate(nums):
+            n = nums[:i] + nums[i+1:]
+            for y in self.permute(n):
+                ans.append([num] + y)
+        return ans
+    
+    def permuteUnique(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: List[List[int]]
+        """
+        ans=self.permute(nums)
+        temp=[]
+        for i in ans:
+            if i in temp:
+                pass
+            else:
+                temp.append(i)
+        return temp

solution/231.Power of Two/Solution.py

@@ -0,0 +1,13 @@
+class Solution:
+    def isPowerOfTwo(self, n):
+        """
+        :type n: int
+        :rtype: bool
+        """
+        if n<=0:
+            return False
+        m=2**32
+        if m%n:
+            return False
+        else:
+            return True