看这个算式 ☆☆☆ + ☆☆☆ = ☆☆☆ 如果每个五角星代表 1 ~ 9 的不同的数字。

package org.bluebridge.topics;

public class FilloutEquation {

public static void main(String[] args) {

int[] data = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

allsort(data, 0);

System.out.println(count);

}

static int count = 0;

public static void allsort(int data[], int i) {

if (i == data.length) {

int a = data[0] * 100 + data[1] * 10 + data[2];

int b = data[3] * 100 + data[4] * 10 + data[5];

int c = data[6] * 100 + data[7] * 10 + data[8];

if (a + b == c)

count++;

return;

}

for (int j = i; j < data.length; j++) {

int temp = data[j];

data[j] = data[i];

data[i] = temp;

allsort(data, i + 1);

temp = data[j];

data[j] = data[i];

data[i] = temp;

}

}

}