数字全排列

#include <cstdio>
int n,m,a[10],arr[10]={3,4,5,6};
void dfs(int v){
if(v >= n){
for(int i = 0;i<n;i++)
printf("%d ",a[i]);
printf("\n");
return ;
}
for(int i = 0; i<m;i++){
a[v] = arr[i];
dfs(v+1);
}
}
int main(){
while(scanf("%d%d",&n,&m)==2){
dfs(0);
}
}

#include <cstdio>
#include <cstring>
int n,m,a[10],arr[10]={3,4,5,6},mark[10];
void dfs(int v){
if(v >= n){
for(int i = 0;i < n;i++)
printf("%d ",a[i]);
printf("\n");
return ;
}
for(int i = 0; i< n;i++){
if(!mark[i]){//用过的标记去重
mark[i] = 1;
a[v] = arr[i];
dfs(v+1);
mark[i] = 0;
}
}
}
int main(){
while(scanf("%d",&n)==1){
memset(mark,0,sizeof(mark));
dfs(0);
}
}

#include <cstdio>
#include <cstring>
#include<algorithm>
using namespace std;
int n,m,a[10],arr[10]={3,4,5,6},mark[10];
void dfs(int v){
if(v > n){
for(int i = 1;i <= n;i++)
printf("%d ",a[i]);
printf("\n");
return ;
}
for(int i = 0; i< n;i++){
//if(!mark[i]){//这种是主函数里进行排序之后就不用比较了
if(!mark[i]&&arr[i]>a[v-1]){//这种就比较一下而已
mark[i] = 1;
a[v] = arr[i];
dfs(v+1);
mark[i] = 0;
}
}
}
int main(){
while(scanf("%d",&n)==1){
memset(mark,0,sizeof(mark));
//sort(arr,arr+4);
a[0]=0;
dfs(1);
}
}