java - 如何从二维数组中查找索引

Question

我想做的是打印二维数组中的最大数字及其索引位置。我能够找到最大的数字，但我似乎不知道如何打印它的索引位置。无论如何，这是我到目前为止所拥有的:

public static void main(String[] args) {
    int[][] arr = {{4, 44, 5, 7, 63, 1}, {7, 88, 31, 95, 9, 6}, {88, 99, 6, 5, 77, 4}};

    double max = arr[0][0];
    for (int i = 0; i < arr.length; i++) {
        for (int j = 0; j < arr.length; j++) {
            if (arr[i][j] > max) {
                max = arr[i][j];

            }
        }
    }
    System.out.println(max);
    System.out.println(i + j); //No idea what I should be doing here, just trying out everything I can think of 

Answer 1

现在，您应该始终获得 2 * arr.length 作为最终值。这可能不是您正在寻找的。看起来您想知道最大值的坐标。为此，您需要缓存索引的值，然后在以后使用它们:

public static void main(String[] args) {
    int[][] arr = {{4, 44, 5, 7, 63, 1}, {7, 88, 31, 95, 9, 6}, {88, 99, 6, 5, 77, 4}};
    int tmpI = 0;
    int tmpJ = 0;
    double max = arr[0][0];
    // there are some changes here. in addition to the caching
    for (int i = 0; i < arr.length; i++) {
        int[] inner = arr[i];
        // caches inner variable so that it does not have to be looked up
        // as often, and it also tests based on the inner loop's length in
        // case the inner loop has a different length from the outer loop.
        for (int j = 0; j < inner.length; j++) {
            if (inner[j] > max) {
                max = inner[j];
                // store the coordinates of max
                tmpI = i; tmpJ = j;
            }
        }
    }
    System.out.println(max);
    // convert to string before outputting:
    System.out.println("The (x,y) is: ("+tmpI+","+tmpJ+")");