四种语言完美实现组合算法

<?php

function rxn($start, $bit, $n, $m) {
static $name = __FUNCTION__;
static $result = array();
static $arr = array();

for ($i=$start; $i<$n-$m+$bit; $i++) {
$arr[$bit-1] = $i;
if ($bit == $m) {
array_push($result, $arr);
} else if ($bit < $m) {
$name($i+1, $bit+1, $n, $m);
}
}
return $result;
}

$result = rxn(0,1, 3,2);

var_dump($result);

var result = [];
var rxn = function(start, bit, arr, n, m) {
var name = arguments.callee;

for (var i=start; i<n+m-bit; i++) {
arr[bit-1] = i;
if (bit == m) {
result.push(Array.prototype.slice.call(arr));
} else if (bit < m) {
name.call(null,i+1, bit+1, arr, n, m);
}
}
}

var n = 3,
m = 2;

ret = rxn(0,1,[],n,m);
console.log(result);

#! /usr/bin/python3

import copy

def rxn(start, bit, arr, n, m, result=[]):
for i in range(start, n+m-bit):
arr[bit-1] = i
if bit == m:
result.append(copy.copy(arr))
elif bit < m:
rxn(i+1, bit+1, arr, n, m)
return result

n, m = 3, 2
result = rxn(0,1,[None for i in range(m)], n, m)

print(result)

package main

import "fmt"

var result [][]int

func rxn(start, bit, n, m int, arr map[int]int) {
for i:=start; i<n+m-bit; i++ {
arr[bit-1] = i
if bit == m{
var t []int
for _, v := range arr {
t = append(t, v)
}
result = append(result, t);
} else if bit < m {
rxn(i+1, bit+1, n, m, arr)
}
}
}

func main() {
n,m := 3,2
arr := make(map[int]int)
rxn(0, 1, n, m, arr)

fmt.Println(result)
}