Cod sursa(job #401912)

Utilizator Dj_AndreiAndrei Tudora Dj_Andrei Data 23 februarie 2010 10:38:21
Problema 12-Perm Scor 0
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.52 kb
#include<stdio.h>
#include<math.h>
#include<iostream.h>
FILE *f=fopen("12perm.in","r");
FILE *g=fopen("12perm.out","w");
long n,st[15000001],k,x;

int valid(int k){
	int i;
	for(i=1;i<k;i++){
		if(st[i]==st[k])
			return 0;
		if(abs(st[i]-st[i+1])>=3)
			return 0;}
	return 1;}

void back(int k){
	int i;
	for(i=1;i<=n;i++){
		st[k]=i;
		if(valid(k))
			if(k==n)
				x++;
		else
			back(k+1);}}


int main (){
	fscanf(f,"%ld",&n);
	back(1);
	fprintf(g,"%ld",x);
	fclose(f);
	fclose(g);
	return 0;}