Week 5

Author: 8804who

implement-trie-prefix-tree/8804who.py

@@ -0,0 +1,39 @@
+class Trie:
+
+    def __init__(self):
+        self.trie = {}
+
+    def insert(self, word: str) -> None:
+        level = self.trie
+        
+        for i in range(len(word)+1):
+            if i==len(word):
+                level['end'] = 0
+                break
+            if word[i] not in level:
+                level[word[i]] = {}
+            level = level[word[i]]
+            
+    def search(self, word: str) -> bool:
+        level = self.trie
+
+        for char in word:
+            if i==len(word):
+                if 'end' in level:
+                    return True
+                else:
+                    return False
+            if word[i] not in level:
+                return False
+            level = level[word[i]]
+
+    def startsWith(self, prefix: str) -> bool:
+        level = self.trie
+
+        for i in range(len(prefix)+1):
+            if i==len(prefix):
+                return True
+            if prefix[i] not in level:
+                return False
+            level = level[prefix[i]]
+    

word-break/8804who.py

@@ -0,0 +1,15 @@
+class Solution:
+    def wordBreak(self, s: str, wordDict: List[str]) -> bool:
+        dp = [False] * (len(s)+1)
+        dp[0] = True
+
+        for i in range(len(s)):
+            if not dp[i]:
+                continue
+            for word in wordDict:
+                if i+len(word)>=len(s)+1:
+                    continue
+                if s[i:i+len(word)] == word:
+                    dp[i+len(word)] = True
+    
+        return dp[-1]