【华为机考E卷】-“找数字/找等值元素”题解思路java

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C0E42 找数字/找等值元素

真题链接：【持续更新】2024华为 OD 机试E卷机考真题库清单（全真题库）

思路

1、遍历二维数组，数字相同的放一起
2、再遍历二维数组，从相同的数字集合中取出元素，计算距离，取最小值

Java

package com.ccr.paper_f;

import java.util.*;

public class C0E42 {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int m = in.nextInt();
        int n = in.nextInt();

        int[][] arr = new int[m][n];
        Map<Integer, List<Point>> map = new HashMap<>(); // 按值来存点
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                arr[i][j] = in.nextInt();
                map.computeIfAbsent(arr[i][j], k -> new ArrayList<>())
                   .add(new Point(i, j, arr[i][j]));
            }
        }

        int[][] mins = new int[m][n];

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {

                List<Point> points = map.get(arr[i][j]);
                int min = Integer.MAX_VALUE;

                // 逐个计算距离
                for (Point p : points) {
                    int distance = p.distance(i, j);
                    if (distance > 0 && distance < min) {   // 0表示自己，跳过
                        min = distance;
                    }
                }
                mins[i][j] = min == Integer.MAX_VALUE ? -1 : min;
            }
        }


        // 打印二维数组
        String[] result = new String[m];
        for (int i = 0; i < m; i++) {
            result[i] = Arrays.toString(mins[i]);
        }
        System.out.println(Arrays.toString(result));
    }


    public static class Point {
        int x;
        int y;
        int value;

        public Point(int x, int y, int value) {
            this.x = x;
            this.y = y;
            this.value = value;
        }

        public int distance(int x, int y) {
            return Math.abs(this.x - x) + Math.abs(this.y - y);
        }
    }
}