在Java中将数组中特定点周围的值相加

Question

所以我有一个用 1 和 0 填充的二维数组。我想检查数组中特定索引的邻居，并将它们的值相加。

第一行和最后一行和列（也称为“边界”值）是特殊情况，因为它们没有完全被相邻值包围，这意味着我必须考虑很多条件。

如果我只做第一个 if 语句，我会遇到 arrayIndexOutOfBounds 的问题。例如，这对我来说很有意义，因为它试图定位 integerGeneration[-1][-1]。

我在下面所做的工作，但它真的很丑，我觉得有一种“更整洁”的方法。

有没有比在它们自己的 else if 语句中处理数组外边界上的所有特殊情况更好的方法？

// checks the inside box
if ((x > 0 & x < rows - 1) & (y > 0 & y < columns - 1)) {
    for (int i = x - 1; i < x + 2; i++) {
        for (int j = y - 1; j < y + 2; j++) {
            filled = integerGeneration[i][j] + filled;
        }
    }
    filled = filled - integerGeneration[x][y];
    return filled;
// checks the top edge
} else if (x == 0 & y < columns - 1 & y > 0) {
    for (int i = x; i < x + 2; i++) {
        for (int j = (y - 1); j < y + 2; j++) {
            filled = integerGeneration[i][j] + filled;
        }
    }
    filled = filled - integerGeneration[x][y];
    return filled;
// checks the left edge
} else if (y == 0 & x < rows - 1 & x > 0) {
    for (int i = x - 1; i < x + 2; i++) {
        for (int j = y; j < y + 2; j++) {
            filled = integerGeneration[i][j] + filled;
        }
    }
    filled = filled - integerGeneration[x][y];
    return filled;
// checks the top left corner
} else if (x == 0 & y == 0) {
    for (int i = x; i < x + 2; i++) {
        for (int j = y; j < y + 2; j++) {
            filled = integerGeneration[i][j] + filled;
        }
    }
    filled = filled - integerGeneration[x][y];
    return filled;
// checks the bottom edge
} else if (x == rows - 1 & y < columns - 1 & y > 0) {
    for (int i = x - 1; i < x + 1; i++) {
        for (int j = y - 1; j < y + 2; j++) {
            filled = integerGeneration[i][j] + filled;
        }
    }
    filled = filled - integerGeneration[x][y];
    return filled;
// checks the right edge
} else if (y == columns - 1 & x < rows - 1 & x > 0) {
    for (int i = x - 1; i < x + 2; i++) {
        for (int j = y - 1; j < y + 1; j++) {
            filled = integerGeneration[i][j] + filled;
        }
    }
    filled = filled - integerGeneration[x][y];
    return filled;
// checks the bottom right corner
} else if (y == columns - 1 & x == rows - 1) {
    for (int i = x - 1; i < x + 1; i++) {
        for (int j = y - 1; j < y + 1; j++) {
            filled = integerGeneration[i][j] + filled;
        }
    }
    filled = filled - integerGeneration[x][y];
    return filled;
// checks the top right corner
} else if (x == 0 & y == columns - 1) {
    for (int i = x; i < x + 2; i++) {
        for (int j = y - 1; j < y + 1; j++) {
            filled = integerGeneration[i][j] + filled;
        }
    }
    filled = filled - integerGeneration[x][y];
    return filled;
// checks the bottom left corner
} else if (x == rows - 1 & y == 0) {
    for (int i = x - 1; i < x + 1; i++) {
        for (int j = y; j < y + 2; j++) {
            filled = integerGeneration[i][j] + filled;
        }
    }
    filled = filled - integerGeneration[x][y];
    return filled;
} else {
    System.out.println("Error, point out of bounds");
    return -1;
}

Answer 1

看看这个：

filled = 0;
for (int i = x - 1; i < x + 2; i++) {
    for (int j = y - 1; j < y + 2; j++) {
        if (i < 0 || i >= rows || j < 0 || j >= columns || i == x || j == y)
            continue;
        filled = integerGeneration[i][j] + filled;
    }
}
return filled;