C语言-数据结构-骑士周游-马踏棋盘问题-源代码

#include<stdio.h>
#include<time.h>
#define title "------------------------------Life is a fight!------------------------------------"
#define X 8 //定义棋盘大小
#define Y 8

int chess[X][Y]= {
{0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0}
};

int sposition(int *x, int *y, int p)
{

switch(p)//特别需要注意每个case 中的顺序，对程序执行的时间有很大影响
{
case 0:
if( *x+2<=X-1 && *y-1>=0 && chess[*x+2][*y-1]==0 )
{
*x = *x + 2;
*y = *y - 1;
return 1;
}
else
return 0;

case 1:
if( *x+2<=X-1 && *y+1<=Y-1 && chess[*x+2][*y+1]==0 )
{
*x = *x + 2;
*y = *y + 1;
return 1;
}
else
return 0;

case 2:
if( *x+1<=X-1 && *y-2>=0 && chess[*x+1][*y-2]==0 )
{
*x = *x + 1;
*y = *y - 2;
return 1;
}
else
return 0;

case 3:
if( *x+1<=X-1 && *y+2<=Y-1 && chess[*x+1][*y+2]==0 )
{
*x = *x + 1;
*y = *y + 2;
return 1;
}
else
return 0;

case 4:
if( *x-2>=0 && *y-1>=0 && chess[*x-2][*y-1]==0 )
{
*x = *x - 2;
*y = *y - 1;
return 1;
}
else
return 0;

case 5:
if( *x-2>=0 && *y+1<=Y-1 && chess[*x-2][*y+1]==0 )
{
*x = *x - 2;
*y = *y + 1;
return 1;
}
else
return 0;

case 6:
if( *x-1>=0 && *y-2>=0 && chess[*x-1][*y-2]==0 )
{
*x = *x - 1;
*y = *y - 2;
return 1;
}
else
return 0;

case 7:
if( *x-1>=0 && *y+2<=Y-1 && chess[*x-1][*y+2]==0 )
{
*x = *x - 1;
*y = *y + 2;
return 1;
}
else
return 0;

default:
return 0;
}
}

void prfChess(int t_chess[][Y])
{
int i, j;
for(i=0;i<X;i++)
{
for(j=0;j<Y;j++)
{
printf("%3d", t_chess[i][j]);
}
printf("\n");
}
}

int searchp(int x, int y, int c)
{
int x1, y1, p=0;
int i, j, flag=0;

x1=x; y1=y;

chess[x1][y1]=c;
//printf("%d\n",c);

if(X*Y==c)  //递归结束条件
{
prfChess(chess);
return 1;
}

flag=sposition(&x1, &y1, p);//找到第一个符合条件的位置
while(0==flag && p<X-1)
{
p++;
flag=sposition(&x1,&y1,p);
}

while(flag) //如果不是死路，即存在往下走的位置
{
if(searchp(x1,y1,c+1))    //继续往下搜索，直到满足c==X*Y,返回1，结束递归
return 1;

x1=x;   //如果是死路一条，则要向后退，回溯到上一个位置
y1=y;

p++;    //将P向后移一个位置，继续搜索其他的可能位置
flag=sposition(&x1,&y1,p);
while(0==flag && p<X-1)
{
flag=sposition(&x1,&y1,++p);
}
}

if(0==flag) //如果经过搜索，没有满足条件的位置，则将该位置的值改回去，变为零
{
chess [x][y]=0;
}
return 0;
}

int main(void)
{
clock_t start, end;
double t;
printf("%s\n\n\n",title);
start=clock();
if(!searchp(2,0,1))
printf("Cannot find!!!\n\n\n");
end=clock();
t=(double)(end-start)/CLOCKS_PER_SEC;
printf("\nUsed %f seconds\n\n\n", t);
return 0;
}