#include <stdio.h>#include <stdlib.h> #define  LOOP         1#define  SWAP(a,b)    { int t; t = a; a = b; b = t; }#define  REVERSE(a,b) { int i, j;                            \                        for (i=(a), j=(b); i < j; i++, j--)  \                             SWAP(perm[i], perm[j]);         \                      }#define  DISPLAY(n)   { int i;                               \                        printf("\n");                        \                        for (i = 0; i < n; i++)              \                             printf("%d ", perm[i]);         \                      }                        void  again(int  perm[], int L, int R){     int  i = R;      while (LOOP) {          if (R - L + 1 > 2) {               again(perm, L+1, R);               DISPLAY(R);          }          if (i > L ) {               SWAP(perm[L], perm[i]);               REVERSE(L+1, R);               DISPLAY(R);               i--;          }          else               break;     }} void permut(int perm[], int n){     int  i;      for (i = 0; i < n; i++)          perm[i] = i + 1;     again(perm, 0, n-1);} #define    MAXSIZE   20 void main(void){     int   perm[MAXSIZE];     char  line[100];     int   n;      gets(line);     n = atoi(line);     permut(perm, n);}

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