java - 从某个元素开始在二维数组中搜索java

Question

我正在尝试编写一个代码来搜索二维数组，并尝试找到最接近“x”的空元素(如果“x”有任何数据)。元素的坐标是从另一种方法给出的。例如“x”是(3,2)。如果没有空元素，则代码必须继续在整个数组中搜索。

public void find(int row, int column) {
    for (int i = row - 1; i < row + 2; i++) {
        for (int k = column - 1; k < column + 2; k++) {

            if (this.arr[i][k].equals(" ")) {
                System.out.println(i + "," + k + " is empty.");
                return;
            }
        }

    }
}

我正在寻找有关如何编写此方法的任何有用建议的前言。谢谢。

Answer 1

根据假设

• 这是矩阵(每行具有相同的列数)
• 方法参数有效:0 <= row < numOfRows和0 <= column < numOfColumns

此代码将以您所描述的方式搜索指定元素周围的二维数组。注意，这不是围绕指定元素的时钟方向循环搜索，而是从左上角到右下角(从上到下，从左到右)搜索

public void find(int row, int column) {
        int distance = 1;
        int numOfRows = arr.length;
        int numOfColumns = 0;
        if (arr.length > 0) {
            numOfColumns = arr[0].length;
        }
        int maxDistance = Math.max(numOfRows, numOfColumns);        
        for (distance = 1; distance < maxDistance; distance ++) {
            for (int i = Math.max(row - distance, 0); i <= Math.min(row + distance, numOfRows - 1); i++) {
                if (Math.abs(i - row) == distance) {
                    // Check row
                    for (int k = Math.max(column - distance, 0); k <= Math.min(column + distance, numOfColumns - 1); k++) {
                        if (arr[i][k] == null || arr[i][k].trim().isEmpty()) {
                            System.out.println((i+1) + "," + (k+1) + " is empty.");
                            return;
                        } else {
                            System.out.println((i+1) + "," + (k+1) + " is not empty.");
                        }
                    }
                } else {
                    // Check only edge elements
                    int k = column - distance;
                    if (k >= 0) {
                        if (arr[i][k] == null || arr[i][k].trim().isEmpty()) {
                            System.out.println((i+1) + "," + (k+1) + " is empty.");
                            return;
                        } else {
                            System.out.println((i+1) + "," + (k+1) + " is not empty.");
                        }
                    }
                    k = column + distance;
                    if (k < numOfColumns) {
                        if (arr[i][k] == null || arr[i][k].trim().isEmpty()) {
                            System.out.println((i+1) + "," + (k+1) + " is empty.");
                            return;
                        } else {
                            System.out.println((i+1) + "," + (k+1) + " is not empty.");
                        }
                    }
                }
            }
        }
        System.out.println("No empty elements");
    }