排列组合的C,Java,JavaScript实现

题目源自: Linux C编程一站式学习的习题

欢迎拍砖~

c版

#include <stdio.h>#define N 5#define M 5#define IS_COMBINATION 1int arr[N];void printArr(void){int j = M,i ;if(IS_COMBINATION){for(i=0;i<M-1;i++){if(arr[i]>arr[i+1])return;}}for(i=0;i<j;i++){printf("%d ",arr[i]);}printf("\n");}void swap(int i , int j){int temp = arr[i];arr[i]=arr[j];arr[j]=temp;}void permutation(int k){int i = N-k;if(k==N-M){printArr();return;}for(;i<N;i++){swap(N-k,i);permutation(k-1);swap(N-k,i);}}int main(void){int i = 0 ;for(;i<N;i++ ){arr[i]=i+1;}permutation(N );return 0;}

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java版

static int N = 5,M=3;static boolean IS_COMBINATION = false;static int[] arr = new int[N];static void print(){if(IS_COMBINATION){        for(int i=0;i<M-1; i++){            if(arr[i]>arr[i+1]){                return;            }            }        }System.out.println(Arrays.toString(Arrays.copyOfRange(arr, 0, M)));}static void swap(int i , int j){arr[i]=arr[j]+0*(arr[j]=arr[i]);}static void permutation(int k){if(k==N-M){print();return;}for (int i = N-k; i < N; i++) {swap(i, N-k);permutation(k-1);swap(i, N-k);}} public static void main(String[] args) {for (int i = 0; i < N; i++) {arr[i]=i+1;}permutation(N);}

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javascript版

var N = 5,M = 1 , IS_COMBINATION = true ;var arr  = [] ;for(var i = 0 ; i<N  ;i++){    arr[i]=i+1;}var print = function(){    if(IS_COMBINATION){        for(var i=0;i<M-1; i++){            if(arr[i]>arr[i+1]){                console.log(arr);                return;            }        }    }    console.log(arr.slice(0,M));}var swap = function(i,j){    arr[i]=arr[j]+0*(arr[j]=arr[i]);}var permutation = function(k){    if(k==N-M){        print();        return;    }    for(var i = N-k ; i< N  ; i++){        swap(N-k,i);        permutation(k-1);        swap(N-k,i);    }}permutation(N);

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