[8804who] WEEK 08 Solutions

clone-graph/8804who.py

@@ -0,0 +1,33 @@
+"""
+# Definition for a Node.
+class Node:
+    def __init__(self, val = 0, neighbors = None):
+        self.val = val
+        self.neighbors = neighbors if neighbors is not None else []
+"""
+
+from typing import Optional
+
+class Solution:
+    def cloneGraph(self, node: Optional['Node']) -> Optional['Node']:
+        if not node:
+            return 
+        visited = {}
+        new_node = Node()
+        def dfs(original_node, new_node):
+            if original_node.val in visited:
+                return
+            visited[original_node.val] = new_node
+            new_node.val = original_node.val
+            new_node.neighbors = []
+
+            for neighbor in original_node.neighbors:
+                new_node.neighbors.append(Node())
+                if neighbor.val not in visited:
+                    dfs(neighbor, new_node.neighbors[-1])
+                new_node.neighbors[-1] = visited[neighbor.val]
+        dfs(node, new_node)
+        return new_node
+
+
+

longest-common-subsequence/8804who.py

@@ -0,0 +1,13 @@
+class Solution:
+    def longestCommonSubsequence(self, text1: str, text2: str) -> int:
+        dp = [[0 for _ in range(len(text2)+1)] for _ in range(len(text1)+1)]
+
+        for i in range(1, len(text1)+1):
+            for j in range(1, len(text2)+1):
+                if text1[i-1] == text2[j-1]:
+                    dp[i][j] = dp[i-1][j-1]+1
+                else:
+                    dp[i][j] = max(dp[i-1][j], dp[i][j-1])
+
+        return dp[-1][-1]
+

longest-repeating-character-replacement/8804who.py

@@ -0,0 +1,26 @@
+class Solution:
+    def characterReplacement(self, s: str, k: int) -> int:
+        n = 65
+        answer = 1
+        for i in range(26):
+            t = chr(n+i)
+            start = 0
+            end = 0
+            x = 1 if s[start] != t else 0
+
+            while True:
+                if x > k:
+                    if s[start] != t:
+                        x -= 1
+                    start += 1
+                else:
+                    end += 1
+                    if end == len(s):
+                        break
+                    if s[end] != t:
+                        x += 1
+                if x <= k:
+                    answer = max(answer, end-start+1)
+        return answer
+
+

palindromic-substrings/8804who.py

@@ -0,0 +1,23 @@
+class Solution:
+    def countSubstrings(self, s: str) -> int:
+        answer = 0
+        for i in range(len(s)):
+            for j in range(len(s)):
+                if i - j < 0 or i + j >= len(s):
+                    break
+                if s[i-j] == s[i+j]:
+                    answer += 1
+                else:
+                    break
+
+            if i+1 >= len(s) or s[i] != s[i+1]:
+                continue
+            for j in range(len(s)):
+                if i - j < 0 or i + 1 + j >= len(s):
+                    break
+                if s[i-j] == s[i+1+j]:
+                    answer += 1
+                else:
+                    break
+        return answer
+

reverse-bits/8804who.py

@@ -0,0 +1,4 @@
+class Solution:
+    def reverseBits(self, n: int) -> int:
+        return int(format(n, "032b")[::-1], 2)
+