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一组围绕数学的类和函数。

里面有什么？

CombinationBuilder

一个用于创建组合的实用类。该类还提供阶乘计算。

示例和用法

Combination

获取5个数中的3个

print_r(CombinationBuilder::getCombination(5, 3));

将输出

Array
(
    [1-2-3] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
        )

    [1-2-4] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 4
        )

    [1-2-5] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 5
        )

    [1-3-4] => Array
        (
            [0] => 1
            [1] => 3
            [2] => 4
        )

    [1-3-5] => Array
        (
            [0] => 1
            [1] => 3
            [2] => 5
        )

    [1-4-5] => Array
        (
            [0] => 1
            [1] => 4
            [2] => 5
        )

    [2-3-4] => Array
        (
            [0] => 2
            [1] => 3
            [2] => 4
        )

    [2-3-5] => Array
        (
            [0] => 2
            [1] => 3
            [2] => 5
        )

    [2-4-5] => Array
        (
            [0] => 2
            [1] => 4
            [2] => 5
        )

    [3-4-5] => Array
        (
            [0] => 3
            [1] => 4
            [2] => 5
        )

)

或以更紧凑的方式

(1, 2, 3)
(1, 2, 4)
(1, 2, 5)
(1, 3, 4)
(1, 3, 5)
(1, 4, 5)
(2, 3, 4)
(2, 3, 5)
(2, 4, 5)
(3, 4, 5)

组合计数

获取可能的组合数量

print_r(CombinationBuilder::getCombinationCount(5, 3));

将输出

10

阶乘

获取5的阶乘（5!）

print_r(CombinationBuilder::factorial(5));

将输出

120