q348.go

package main;

import (
    "fmt"
)

var memo = [][]int {};

func init() {
    memo = make([][]int, 100000);
    for i := 0; i < 100; i++ {
        memo[i] = make([]int, 100000);
    }
}

func ackermann(m, n int) int {
    res := 0;
    v := memo[m][n];
    if (v != 0) {
        res = v;
    } else {
        switch {
        case m == 0:
            res = n + 1;
        case n == 0:
            res = ackermann(m - 1, 1);
        default:
            res = ackermann(m - 1, ackermann(m, n - 1));
        }
        memo[m][n] = res;
    }

    return res;
}

func main() {
    fmt.Printf("ackermann(2, 1) = %d\n", ackermann(2, 1));
    fmt.Printf("ackermann(2, 2) = %d\n", ackermann(2, 2));
    fmt.Printf("ackermann(3, 4) = %d\n", ackermann(3, 4));
    fmt.Printf("ackermann(4, 1) = %d\n", ackermann(4, 1));
}

CodeIQ アッカーマンの呪い
2次元配列のスマートな初期化の方法を考えるのが面倒臭かったので、とりあえず力技で。