#include<iostream> #include<cstring> #define N 4 using namespace std; int rec[N]; bool used[N]; int count=0; void Print(){ for(int i=0;i<N;i++) cout<<rec[i]<<" "; cout<<endl; } void Try(int s){ int j=0; while(j<N){ if(!used[j]){ rec[s]=j; if(s==N-1){ count++; Print(); } used[j]=true; Try(s+1); used[j]=false; } j++; } } int main(){ memset(used,false,sizeof(used)); Try(0); cout<<count<<endl; return 0; }
