2019-11-14

Author: Jiayang Wu

0299.猜数字游戏/0299-猜数字游戏.py

@@ -0,0 +1,22 @@
+class Solution(object):
+    def getHint(self, secret, guess):
+        """
+        :type secret: str
+        :type guess: str
+        :rtype: str
+        """
+        from collections import Counter
+        dic_s = Counter(secret)
+        dic_g = Counter(guess)
+        
+        a, b = 0, 0
+        for i in range(len(secret)):
+            if secret[i] == guess[i]:
+                a += 1
+                dic_s[secret[i]] -= 1
+                dic_g[secret[i]] -= 1
+                
+        for i in dic_s & dic_g:
+            b += min(dic_s[i], dic_g[i])
+            
+        return "{}A{}B".format(a, b)

0315.计算右侧小于当前元素的个数/0315-计算右侧小于当前元素的个数.py

@@ -0,0 +1,35 @@
+class TreeNode(object):
+    def __init__(self, val):
+        self.left = None
+        self.right = None
+        self.val = val
+        self.left_subtree_cnt = 0
+        
+class Solution(object):
+    def countSmaller(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: List[int]
+        """
+        
+        # 从左往右处理，右边是未知的，所以不好弄
+        # 从右往左处理，则对于每个数，其右边的数都已知
+        res = [0 for _ in nums]
+        root = None
+        for i, num in enumerate(nums[::-1]):
+            root = self.insert(root, num, i, res)
+        return res[::-1]
+    
+    def insert(self, root, val, i, res):
+        if not root:
+            root = TreeNode(val)
+        elif root.val >= val:
+            root.left_subtree_cnt += 1
+            root.left = self.insert(root.left, val, i, res)
+        elif root.val < val:
+            res[i] += root.left_subtree_cnt + 1
+            root.right = self.insert(root.right, val, i, res)
+            
+        return root
+            
+            

1055.形成字符串的最短路径/1055-形成字符串的最短路径.py

@@ -5,33 +5,21 @@ def shortestWay(self, source, target):
         :type target: str
         :rtype: int
         """
-
-        import collections
-        dicse = collections.Counter(source)
-        dictt = collections.Counter(target)
-
-        for key, val in dictt.items():
-            if dicse.get(key, 0) == 0:
+        s = set(source)
+        t = set(target)
+        for ch in t:
+            if ch not in s:
                 return -1
-
-        cnt = 0
-        start, end = 0, 0
-        i = 0
-        while(i < len(target)):
-            char = target[i]
-            while(source[start] != char): #找起点，一定能找到
-                start += 1
-            end = start + 1
-
-            i += 1
-            while(i < len(target) and end < len(source)):
-                if source[end] == target[i]: #找最长的子序列
-                    i += 1
-                end += 1
-
-            cnt += 1
-            start = 0 #重置起点，为下一轮做准备
 
-        return cnt
-
-            
+        i, j = 0, 0
+        res = 0
+        while j < len(target):
+            i = 0
+            while i < len(source) and j < len(target):
+                if source[i] == target[j]:
+                    i += 1
+                    j += 1
+                else:
+                    i += 1
+            res += 1
+        return res