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【2024华为OD-E卷-100分-箱子之字形摆放】((题目+思路+Java&C++&Python解析)

题目描述

给定一个宽度为 width 的仓库,要求将 n 个箱子按之字形(Zigzag)方式摆放。每个箱子的宽度都是 1,箱子必须摆放在仓库的同一层上,且摆放过程中不能重叠。

之字形摆放的定义是:箱子交替地向左和向右对齐。即第1行从左对齐,第2行从右对齐,第3行再次从左对齐,以此类推。

需要输出按之字形摆放箱子后,每一层的最大高度。

输入

  • 第一行包含两个整数 n 和 width,分别表示箱子的数量和仓库的宽度。
  • 第二行包含 n 个整数,表示每个箱子的高度。

输出

  • 输出一个整数数组,表示每一层的最大高度。

示例

输入

6 4
2 3 4 1 2 3

输出

[4 3 3]

解释

仓库宽度为4,6个箱子按之字形摆放如下:

2 3 4 1
      2
      3

每一层的最大高度分别是:4、3、3。

思路

  1. 计算层数:由于箱子是按之字形摆放,我们可以计算出所需的层数。层数可以通过 ceil(n / width) 计算得到,其中 ceil 表示向上取整。
  2. 记录每层的最大高度:使用一个数组来记录每一层的最大高度。
  3. 遍历箱子:按序遍历每个箱子,计算其在第几层以及是向左还是向右对齐。
  4. 更新当前层的最大高度:根据箱子的当前位置和高度,更新对应层的最大高度。

Java 实现

import java.util.*;

public class ZigzagBoxes {
    public static int[] getMaxHeights(int n, int width, int[] heights) {
        int layers = (int) Math.ceil((double) n / width);
        int[] maxHeights = new int[layers];

        for (int i = 0; i < n; i++) {
            int layer = i / width;
            int positionInLayer = i % width;
            boolean leftAligned = layer % 2 == 0;

            int columnIndex = leftAligned ? positionInLayer : width - 1 - positionInLayer;
            maxHeights[layer] = Math.max(maxHeights[layer], heights[i]);

            // To keep track of the effective max height at each "virtual" column position within the layer
            // (for debugging/visualization purposes, not needed for final solution)
            // This part is commented out as it's not required by the problem statement
            /*
            if (leftAligned) {
                // Left-aligned layer visualization (not needed for solution)
                System.out.print(heights[i] + " ");
            } else {
                // Right-aligned layer visualization with adjusted indexing (not needed for solution)
                System.out.print(heights[i] + " ".repeat(width - positionInLayer - 1));
                System.out.print(heights[i] + " | ");
            }
            if ((i + 1) % width == 0) System.out.println();
            */
        }

        return maxHeights;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int width = scanner.nextInt();
        int[] heights = new int[n];
        for (int i = 0; i < n; i++) {
            heights[i] = scanner.nextInt();
        }
        int[] result = getMaxHeights(n, width, heights);
        for (int height : result) {
            System.out.print(height + " ");
        }
    }
}

C++ 实现

#include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>

std::vector<int> getMaxHeights(int n, int width, const std::vector<int>& heights) {
    int layers = std::ceil(static_cast<double>(n) / width);
    std::vector<int> maxHeights(layers, 0);

    for (int i = 0; i < n; ++i) {
        int layer = i / width;
        int positionInLayer = i % width;
        bool leftAligned = layer % 2 == 0;

        int columnIndex = leftAligned ? positionInLayer : width - 1 - positionInLayer;
        // Note: columnIndex is used here just for logical understanding,
        // but actually we directly update the max height of the current layer
        maxHeights[layer] = std::max(maxHeights[layer], heights[i]);
    }

    return maxHeights;
}

int main() {
    int n, width;
    std::cin >> n >> width;
    std::vector<int> heights(n);
    for (int i = 0; i < n; ++i) {
        std::cin >> heights[i];
    }
    std::vector<int> result = getMaxHeights(n, width, heights);
    for (int height : result) {
        std::cout << height << " ";
    }
    return 0;
}

Python 实现

def get_max_heights(n, width, heights):
    layers = math.ceil(n / width)
    max_heights = [0] * layers

    for i in range(n):
        layer = i // width
        position_in_layer = i % width
        left_aligned = layer % 2 == 0

        column_index = position_in_layer if left_aligned else width - 1 - position_in_layer
        # Note: column_index is not used directly in final calculations,
        # but helps in understanding the logical arrangement
        max_heights[layer] = max(max_heights[layer], heights[i])

    return max_heights

import math
import sys
input = sys.stdin.read
data = input().split()

n = int(data[0])
width = int(data[1])
heights = list(map(int, data[2:n+2]))

result = get_max_heights(n, width, heights)
print(" ".join(map(str, result)))

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