day 14

Author: Your Name

139WordBreak.py

@@ -0,0 +1,29 @@
+class Solution(object):
+    def wordBreak(self, s, wordDict):
+        """
+        :type s: str
+        :type wordDict: List[str]
+        :rtype: bool
+        s = "catsandog", wordDict = ["cats","dog","sand","and","cat"]
+        """
+        from collections import defaultdict
+        mymap = defaultdict()
+        mymap[0] = True
+        def helper(end):
+            if end in mymap:
+                return mymap[end]
+            res = False
+            for i in wordDict:
+                if s[0:end].endswith(i):
+                    res = res or helper(end - len(i))
+                    if res:
+                        mymap[end] = res
+                        return res
+            mymap[end] = res
+            return res
+        res = helper(len(s))
+        return res
+
+sol = Solution()
+res = sol.wordBreak(s = "applepenapple", wordDict = ["apple","pen"])
+print(res)

198HouseRobber.py

@@ -0,0 +1,30 @@
+class Solution(object):
+    def rob(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        [2,7,9,3,1]
+        12
+        2 -> 2
+        2 7 -> 7
+        2 7 9 -> 11
+        2 7 9 3 -> 11
+        """
+        if len(nums) == 1:
+            return nums[0]
+        from collections import defaultdict
+        self.map = defaultdict()
+        self.map[0] = nums[0]
+        self.map[1] = max(nums[0], nums[1])
+        def helper(n):
+            # must rob last
+            # don't rob last
+            if n in self.map:
+                return self.map[n]
+            res = max(helper(n-1), helper(n-2) + nums[n])
+            self.map[n] = res
+            return res
+        return helper(len(nums) - 1)
+sol = Solution()
+res = sol.rob([2, 7, 9, 3, 1])
+print(res)

322.CoinChange.py

@@ -0,0 +1,36 @@
+class Solution(object):
+    def coinChange(self, coins, amount):
+        """
+        :type coins: List[int]
+        :type amount: int
+        :rtype: int
+        coins = [1,2,5], amount = 11
+        5 + 5 + 1
+        """
+        if amount == 0:
+            return 0
+        from collections import defaultdict
+        mymap = defaultdict()
+        for i in coins:
+            mymap[i] = 1
+        minval = min(coins)
+        def helper(total):
+            if total in mymap:
+                return mymap[total]
+            if total < minval:
+                return -1
+            res = float("inf")
+            for i in coins:
+                tmp = helper(total - i)
+                if tmp == -1:
+                    continue
+                res = min(res, tmp + 1)
+            mymap[total] = res
+            if res == float("inf"):
+                return -1
+            return res
+        return helper(amount)
+
+sol = Solution()
+res = sol.coinChange([2], 3)
+print(res)

70ClimbingStairs.py

@@ -0,0 +1,21 @@
+class Solution(object):
+    def __init__(self):
+        from collections import defaultdict
+        self.map = defaultdict()
+        self.map[1] = 1
+        self.map[2] = 2
+    def climbStairs(self, n):
+        """
+        :type n: int
+        :rtype: int
+        """
+        if n in self.map:
+            return self.map[n]
+        res = self.climbStairs(n-1) + self.climbStairs(n - 2)
+        self.map[n] = res
+        return res
+
+
+sol = Solution()
+res = sol.climbStairs(10)
+print(res)