马踏棋盘算法（回溯算法、X*Y图的邻接矩阵深度优先遍历）

#include <stdio.h>
#include <time.h>

#define X 8
#define Y 8

int chess[X][Y];
//找到基于(x,y)位置的下一个可走的位置
int nextxy(int* x,int* y,int count)
{
    switch(count)
    {
    case 0:
        if(*x+2<=X-1&&*y-1>=0&&chess[*x+2][*y-1]==0)
        {
            *x+=2;
            *y-=1;
            return 1;
        }
        break;
    case 1:
        if(*x+2<=X-1&&*y+1<=Y-1&&chess[*x+2][*y+1]==0)
        {
            *x+=2;
            *y+=1;
            return 1;
        }
        break;
    case 2:
        if(*x+1<=X-1&&*y-2>=0&&chess[*x+1][*y-2]==0)
        {
            *x+=1;
            *y-=2;
            return 1;
        }
        break;
    case 3:
        if(*x+1<=X-1&&*y+2<=Y-1&&chess[*x+1][*y+2]==0)
        {
            *x+=1;
            *y+=2;
            return 1;
        }
        break;
    case 4:
        if(*x-2>=0&&*y-1>=0&&chess[*x-2][*y-1]==0)
        {
            *x-=2;
            *y-=1;
            return 1;
        }
        break;
    case 5:
        if(*x-2>=0&&*y+1<=Y-1&&chess[*x-2][*y+1]==0)
        {
            *x-=2;
            *y+=1;
            return 1;
        }
        break;
    case 6:
        if(*x-1>=0&&*y-2>=0&&chess[*x-1][*y-2]==0)
        {
            *x-=1;
            *y-=2;
            return 1;
        }
        break;
    case 7:
        if(*x-1>=0&&*y+2<=Y-1&&chess[*x-1][*y+2]==0)
        {
            *x-=1;
            *y+=2;
            return 1;
        }
        break;

    default:
        break;
    }
    return 0;
}
void print()
{
    int i,j;
    for(i=0;i<X;i++)
    {
        for(j=0;j<Y;j++)
        {
            printf("%2d\t",chess[i][j]);
        }
        printf("\n");
    }
    printf("\n");
}
//深度优先遍历棋盘算法
//(x,y)为位置坐标
//tag是标记变量,每走一步，tag+1
int TravelChessBoard(int x,int y,int tag)
{
    int x1=x,y1=y,flag=0,count=0;
    chess[x][y]=tag;

    if(X*Y==tag)
    {
        print();
        //打印棋盘
        return 1;
    }

    //找到马的下一个可走的坐标(x1,y1),如果找到flag=1,否则为0
    flag = nextxy(&x1,&y1,count);
    while(0==flag && count <7)
    {
        count++;
        flag = nextxy(&x1,&y1,count);
    }

    while(flag)
    {
        if(TravelChessBoard(x1,y1,tag+1))
        {
            return 1;
        }
        //继续找到马的下一个可走的坐标(x1,y1),如果找到flag=1,否则为0
        x1=x;
        y1=y;
        count++;
        flag = nextxy(&x1,&y1,count);
        while(0==flag && count <7)
        {
            count++;
            flag = nextxy(&x1,&y1,count);
        }
    }
    if(0==flag)
    {
        chess[x][y]=0;
    }
    return 0;
}
int main()
{
    int i,j;
    clock_t start,finsh;
    start=clock();
    for(i=0;i<X;i++)
        for(j=0;j<Y;j++)
            {
                chess[i][j]=0;
            }
    if(!TravelChessBoard(2,0,1))
    {
        printf("抱歉，马踏棋盘失败鸟\n");
    }
    finsh=clock();
    printf("本次计算用时%f秒\n\n",(double)(finsh-start)/CLOCKS_PER_SEC);
    return 0;
}