java - 如何在 Java 中检查二维数组是否占对角线

Question

嘿伙计们，我想创建一个函数来检查二维数组是否对角占优

有什么想法吗？

我已经设法找到对角线，但如何检查对角线是否占优？

public static int arraySum(int[][] array){
    int total = 0;

    for (int row = 0; row < array.length; row++)
    {

        total += array[row][row];
    }

    return total;
}

Answer 1

根据Wikipedia ，对角占优矩阵是这样的矩阵:

for every row of the matrix, the magnitude of the diagonal entry in a row is larger than or equal to the sum of the magnitudes of all the other (non-diagonal) entries in that row.

这只是检查弱对角优势，给定一个 2D 数组:

public boolean isDiagonallyDominant(int[][] array) {
    int otherTotal = 0;

    // Loop through every row in the array
    for(int row = 0; row < array.length; row++) {
        otherTotal = 0;

        // Loop through every element in the row
        for(int column = 0; column < array[row].length; column++) {

            // If this element is NOT on the diagonal
            if(column != row) {

                // Add it to the running total
                otherTotal += Math.abs(array[row][column]);
            }
        }

        // If this diagonal element is LESS than the sum of the other ones...
        if(Math.abs(array[row][row]) < otherTotal) {

            // then the array isn't diagonally dominant and we can return.
            return false;
        }
    }
    return true;
}