java是一个范围内的所有毕达哥拉斯三胞胎

Question

如果我想找到特定范围内的所有毕达哥拉斯三胞胎，我编写了以下代码：

for (int a = 1; a < range; a++) {
        for (int b = 1; b < range; b++) {
            for (int c = 1; c < range; c++) {
                if (a * a + b * b == c * c) {
                    System.out.println(a + "," + b + "," + c);
                }
            }
        }
    }

但不幸的是，我得到了重复的三胞胎，例如：3,4,5和4,3,5
我怎样才能克服这个问题

Answer 1

您可以通过更改循环来删除重复项，尤其是在每个循环开始时：

for (int a = 1; a < range; a++) {
        for (int b = a + 1; b < range; b++) {
            for (int c = b + 1; c < range; c++) {
                if (a * a + b * b == c * c) {
                    System.out.println(a + "," + b + "," + c);
                }
            }
        }
    }

请注意，内部循环是不必要的，因为您可以直接从a和b计算c。您只需检查计算值是否为整数：

for (int a = 1; a < range; a++) {
        for (int b = a + 1; b < range; b++) {
            double c = Math.sqrt(a*a + b*b)
            if (c == int(c)) {
                System.out.println(a + "," + b + "," + c);
            }
        }
    }