【Grind75Hard】4問目295. Find Median from Data Stream

grind75_hard/04_295. Find Median from Data Stream/level_1.py

@@ -0,0 +1,44 @@
+# 毎回ソートする
+# TimeOut
+class MedianFinder:
+    def __init__(self):
+        self.nums = []
+
+    def addNum(self, num: int) -> None:
+        self.nums.append(num)
+        self.nums.sort()
+
+    def findMedian(self) -> float:
+        if len(self.nums) % 2:
+            index = len(self.nums) // 2
+            return float(self.nums[index])
+
+        else:
+            index = len(self.nums) // 2
+            return (self.nums[index - 1] + self.nums[index]) / 2
+
+
+# heapを2つ使う
+# 半分より大きい値をいれるheapと小さい値をいれるheapの2種類を使って真ん中の値を取得する
+class MedianFinder:
+
+    def __init__(self):
+        self.low_heap = []
+        self.high_heap = []
+        self.count = 0
+
+    def addNum(self, num: int) -> None:
+        heapq.heappush(self.high_heap, num)
+        high_min = heapq.heappop(self.high_heap)
+        heapq.heappush(self.low_heap, -high_min)  # low_heapは降順にしたいので-1をかける
+        if len(self.high_heap) < len(self.low_heap):
+            low_max = -heapq.heappop(self.low_heap)
+            heapq.heappush(self.high_heap, low_max)
+
+    def findMedian(self) -> float:
+        if (len(self.high_heap) + len(self.low_heap)) % 2:
+            return float(self.high_heap[0])
+        else:
+            middle_low = -self.low_heap[0]
+            middle_high = self.high_heap[0]
+            return (middle_low + middle_high) / 2

grind75_hard/04_295. Find Median from Data Stream/level_2.py

@@ -0,0 +1,17 @@
+# 挿入ソート的に解く
+class MedianFinder:
+
+    def __init__(self):
+        self.nums = []
+
+    def addNum(self, num: int) -> None:
+        index = bisect_left(self.nums, num)
+        self.nums.insert(index, num)
+
+    def findMedian(self) -> float:
+        if len(self.nums) % 2:
+            return float(self.nums[len(self.nums) // 2])
+        else:
+            high_index = len(self.nums) // 2
+            low_index = high_index - 1
+            return (self.nums[low_index] + self.nums[high_index]) / 2

grind75_hard/04_295. Find Median from Data Stream/level_3.py

@@ -0,0 +1,16 @@
+class MedianFinder:
+
+    def __init__(self):
+        self.nums = []
+
+    def addNum(self, num: int) -> None:
+        index = bisect_left(self.nums, num)
+        self.nums.insert(index, num)
+
+    def findMedian(self) -> float:
+        if len(self.nums) % 2:
+            return float(self.nums[len(self.nums) // 2])
+        else:
+            high_index = len(self.nums) // 2
+            low_index = high_index - 1
+            return (self.nums[high_index] + self.nums[low_index]) / 2

grind75_hard/04_295. Find Median from Data Stream/level_4.py

@@ -0,0 +1,15 @@
+class MedianFinder:
+
+    def __init__(self):
+        self.nums = []
+
+    def addNum(self, num: int) -> None:
+        index = bisect_left(self.nums, num)
+        self.nums.insert(index, num)
+
+    def findMedian(self) -> float:
+        if len(self.nums) % 2 == 1:
+            return float(self.nums[len(self.nums) // 2])
+        high_index = len(self.nums) // 2
+        low_index = high_index - 1
+        return (self.nums[high_index] + self.nums[low_index]) / 2

grind75_hard/04_295. Find Median from Data Stream/level_5.py

@@ -0,0 +1,14 @@
+class MedianFinder:
+
+    def __init__(self):
+        self.nums = []
+
+    def addNum(self, num: int) -> None:
+        index = insort_left(self.nums, num)
+
+    def findMedian(self) -> float:
+        if len(self.nums) % 2 == 1:
+            return float(self.nums[len(self.nums) // 2])
+        high_index = len(self.nums) // 2
+        low_index = high_index - 1
+        return (self.nums[high_index] + self.nums[low_index]) / 2