Priority Queue & Hash Table

Coding Test/23.py

@@ -0,0 +1,33 @@
+import re
+import collections
+import itertools
+import heapq
+import bisect
+import sys
+# Definition for singly-linked list.
+class ListNode:
+    def __init__(self, val=0, next=None):
+        self.val = val
+        self.next = next
+class Solution:
+    def mergeKLists(self, lists: List[ListNode]) -> ListNode:
+        heap = []
+        root = result = ListNode(None)
+
+        for i, list in enumerate(lists):
+            if list:
+                heapq.heappush(heap, (list.val, i, list))
+
+        while heap:
+            node = heapq.heappop(heap)
+
+            idx = node[1]
+            result.next = node[2]
+
+            result = result.next
+
+            if result.next:
+                heapq.heappush(heap, (result.next.val, idx, result.next))
+
+
+        return root.next

Coding Test/347.py

@@ -0,0 +1,3 @@
+class Solution:
+    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
+        return list(zip(*collections.Counter(nums).most_common(k)))[0]

README.md

@@ -24,8 +24,9 @@
    > 책: 20, 739, 225, 622, 316
    > 856
 4. Deque, Priority Queue
+   > 책: 23
 5. Hash Table
-   > 771
+   > 771, 347
 6. Graph
    > 200, 17, 46, 77, 39, 78, 332, 207
 7. Shortest Path