Cod sursa(job #154564)

Utilizator sandyxpSanduleac Dan sandyxp Data 11 martie 2008 12:01:00
Problema Generare de permutari Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.81 kb
// permutari cu dancing links
#include <stdio.h>
#include <stdlib.h>

#define MAXN 8

int n, A[MAXN];
struct item { int x; item *l, *r; } P[MAXN], st;

void perm(int k) {
    if (k==n) {
        for (int i = 0; i < n; ++i) {
            printf("%d ", A[i]);
        }
        printf("\n");
        return;
    }
    for (item *p = st.r; p; p = p->r) {
        A[k] = p->x;
        // ascund
        if (p->l)  p->l->r = p->r;
        if (p->r)  p->r->l = p->l;
        perm(k+1);
        // refac
        if (p->l)  p->l->r = p;
        if (p->r)  p->r->l = p;
    }
}

int main()
{
    fscanf(fopen("permutari.in", "r"), "%d", &n);
    for (int i=0; i<n; ++i)
        P[i] = (item) { i+1, i?&P[i-1]:&st, i+1==n?0:&P[i+1] };
    st.r = &P[0]; P[0].l = &st;
    freopen("permutari.out", "w", stdout);
    perm(0);
    return 0;
}