农民过河问题

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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
//this program is edited by 200624101101杨振平
//this paper's edited time is DEC 5th,2008

#define MAX_STEP 20

//index: 0 - 狼，1－羊，2－菜，3－农夫，value：0－本岸，1－对岸
int a[MAX_STEP][4];
int b[MAX_STEP];
//define the thing to take
char *name[] =
{
"空手",
"带狼",
"带羊",
"带菜"
};
//implement search function
void search(int iStep)
{
int i;
if (a[iStep][0] + a[iStep][1] + a[iStep][2] + a[iStep][3] == 4)
{
  for (i = 0; i < iStep; i++)
  {
   if (a[i][3] == 0)
   {
    printf("%s到对岸/n", name[b[i] + 1]);
   }
   else
   {
    printf("%s回本岸/n", name[b[i] + 1]);
   }
  }
printf("/n");
return;
}
for (i = 0; i < iStep; i++)
{
  if (memcmp(a[i], a[iStep], sizeof(a[i])) == 0)
  {
   return;
  }
}
if (a[iStep][1] != a[iStep][3] && (a[iStep][2] == a[iStep][1] || a[iStep][0] == a[iStep][1]))
{
  return;
}
for (i = -1; i <= 2; i++)
{
  b[iStep] = i;
  memcpy(a[iStep + 1], a[iStep], sizeof(a[iStep + 1]));
  a[iStep + 1][3] = 1 - a[iStep + 1][3];
  if (i == -1)
  {
   search(iStep + 1);
  }
  else if (a[iStep][i] == a[iStep][3])
  {
   a[iStep + 1][i] = a[iStep + 1][3];
   search(iStep + 1);
  }
}
}
//main function
void main()
{
search(0);
}
/*运行结果如下：
带羊到对岸
空手回本岸
带狼到对岸
带羊回本岸
带菜到对岸
空手回本岸
带羊到对岸

带羊到对岸
空手回本岸
带菜到对岸
带羊回本岸
带狼到对岸
空手回本岸
带羊到对岸
*/