无法在 python 中打印二进制堆

Question

我尝试在 python 中创建一个二进制堆，但我无法打印它。我确保程序中的逻辑是正确的，但是当我想尝试打印它时，我得到了错误的结果。这就是我想要的程序输出：

输入：

输出：

7
3

命令 1 插入数字
命令 2 显示最高数字
命令 3 删除最高数字

这是我的程序：

class BinaryHeap:
    def __init__(self):
        self.items = []
 
    def size(self):
        return len(self.items)
 
    def parent(self, i):
        return (i - 1)//2
 
    def left(self, i):
        return 2*i + 1
 
    def right(self, i):
        return 2*i + 2
 
    def get(self, i):
        return self.items[i]
 
    def get_max(self):
        if self.size() == 0:
            return None
        return self.items[0]
 
    def extract_max(self):
        if self.size() == 0:
            return None
        largest = self.get_max()
        self.items[0] = self.items[-1]
        del self.items[-1]
        self.max_heapify(0)
        return largest
 
    def max_heapify(self, i):
        l = self.left(i)
        r = self.right(i)
        if (l <= self.size() - 1 and self.get(l) > self.get(i)):
            largest = l
        else:
            largest = i
        if (r <= self.size() - 1 and self.get(r) > self.get(largest)):
            largest = r
        if (largest != i):
            self.swap(largest, i)
            self.max_heapify(largest)
 
    def swap(self, i, j):
        self.items[i], self.items[j] = self.items[j], self.items[i]
 
    def insert(self, key):
        index = self.size()
        self.items.append(key)
 
        while (index != 0):
            p = self.parent(index)
            if self.get(p) < self.get(index):
                self.swap(p, index)
            index = p
 
bheap = BinaryHeap()
 
n = int(input())
for i in range (n):
    operation= input('What would you like to do? ').split()
    if operation == 1:
        data = int(operation[1])
        bheap.insert(data)
    elif operation == 2:
        print('Maximum value: {}'.format(bheap.get_max()))
    elif operation  == 3:
        print('Maximum value removed: {}'.format(bheap.extract_max()))
    elif operation == 4:
        break

我需要你的意见来修复它。

Answer 1

operation 是一个列表（您调用了 split），但您在 if 语句中将其作为 int 进行比较。此外，您应该将其与“1”、“2”、...而不是 1、2、...

进行比较

所以：

    operation = input('What would you like to do? ').split()
    if operation[0] == "1":
        data = int(operation[1])
        bheap.insert(data)
    elif operation[0] == "2":
        print('Maximum value: {}'.format(bheap.get_max()))
    elif operation[0]  == "3":
        print('Maximum value removed: {}'.format(bheap.extract_max()))
    elif operation[0] == "4":
        break

如果您只想在输出中使用 7 和 3，并且仅在输入已完全处理后，那么您应该删除那些冗长的 print 语句（您输出的位置短语），而是收集输出——例如在列表中：

output = []
n = int(input())
for i in range(n):
    operation = input('What would you like to do? ').split()
    if operation[0] == "1":
        data = int(operation[1])
        bheap.insert(data)
    elif operation[0] == "2":
        output.append(bheap.get_max())
    elif operation[0]  == "3":
        bheap.extract_max()
    elif operation[0] == "4":
        break

print("\n".join(map(str, output)))

无法在 python 中打印二进制堆

Can't print binary heap in python

python

binary-heap