Ackerman数学函数
Ackerman数学函数
1 ;; Scheme code
2 (define (ackermann x y)
3 (cond
4 ((= y 0) 0)
5 ((= x 0) (* 2 y))
6 ((= y 1) 2)
7 (else (ackermann (- x 1)
8 (ackermann x (- y 1))))))
这是个神马函数，增长速度太快
(ackermann 4 3)就把我内存算爆掉.
前面几个简单序列
1 (define (foo1 n) (ackermann 0 n))
2 // The value is 2*n
3
4 (define (foo2 n) (ackermann 1 n))
5 // The value is 2^n
6
7 (define (foo3 n) (ackermann 2 n))
8 // The value is 2^2^...^2 which has n 2
