独立钻石跳棋问题

//参考 ：http://blog.sina.com.cn/s/blog_510ad0640100bo3d.html

#include <iostream>
#include <fstream>
using namespace std;

struct step //记录移动棋子的信息
{
int sx, sy; // 记录移动棋子前棋子的位置
int tx, ty; // 记录移动棋子后棋子的位置
int dir; // dir值代表移动棋子的方向
};

struct step mystack[100], last_step;
char diamond[7][7];
int Left_diamond;
int x, y, nx, ny, ndir, top; // ndir值代表方向, 0代表向右, 1代表向下, 2代表向左, 3代表向上
int endx, endy;  //终止方格坐标
int n;  //初始钻石个数

void Init_diamond()
{
for(int i=0; i<7; i++)
{
for(int j=0; j<7; j++)
{
if((i<2 || i>4) && (j<2 || j>4))  //棋盘外
continue;
else
diamond[i][j] = '!';  //空方格
}
}

ifstream fin("独立钻石跳棋.txt");
cout << "输入棋子数：";
fin >> n;  cout << n << endl;
Left_diamond = n;
cout << "输入棋子位置：\n";
int x, y;
for(i=0; i<n; i++)
{
fin >> y >> x;
cout << x << " " << y << endl;
diamond[x][y] = '*';  //钻石
}
cout << "输入终止方格坐标：";
fin >> endx >> endy;
}

int Move_diamond(int y, int x, int dir)
{
if(diamond[y][x] != '*')
{
return 0;
}
struct step temp;
switch(dir)
{
case 0:  //向右走
if(x+2>6 || diamond[y][x+1]!='*' || diamond[y][x+2]!='!')
{
return 0;
}
diamond[y][x] = diamond[y][x+1] = '!';
diamond[y][x+2] = '*';
temp.sx = x;
temp.sy = y;
temp.tx = x+2;
temp.ty = y;
temp.dir = dir;
mystack[top++] = temp;
return 1;
break;
case 1:  //向下走
if(y+2>6 || diamond[y+1][x]!='*' || diamond[y+2][x]!='!')
{
return 0;
}
diamond[y][x] = diamond[y+1][x] = '!';
diamond[y+2][x] = '*';
temp.sx = x;
temp.sy = y;
temp.tx = x;
temp.ty = y+2;
temp.dir = dir;
mystack[top++] = temp;
return 1;
break;
case 2:  //向左走
if(x-2<0 || diamond[y][x-1]!='*' || diamond[y][x-2]!='!')
{
return 0;
}
diamond[y][x] = diamond[y][x-1] = '!';
diamond[y][x-2] = '*';
temp.sx = x;
temp.sy = y;
temp.tx = x-2;
temp.ty = y;
temp.dir = dir;
mystack[top++] = temp;
return 1;
break;
case 3:  //向上走
if(y-2<0 || diamond[y-1][x]!='*' || diamond[y-2][x]!='!')
{
return 0;
}
diamond[y][x] = diamond[y-1][x] = '!';
diamond[y-2][x] = '*';
temp.sx = x;
temp.sy = y;
temp.tx = x;
temp.ty = y-2;
temp.dir = dir;
mystack[top++] = temp;
return 1;
break;
default:
break;
}
return 0;
}

int main()
{
Init_diamond();

top = nx = ny = ndir = 0;
// 回溯遍历，直到找到一个解
while(1)
{
if(Left_diamond == 1 && (diamond[endx][endy] == '*' || (endx==0 && endy==0))) //结束
{
break;
}
for(y=ny; y<7; y++,nx=0)
{
for(x=nx; x<7; x++,ndir=0)
{
for(int dir=ndir; dir<4; dir++)
{
if(Move_diamond(y, x, dir))
{
Left_diamond--;
nx = ny = ndir = 0;
goto nextstep;
}
}
}
}
nextstep:
if(y == 7)
{
top--;
// 回到上一步， 并改变方向
if(top >= 0)
{
last_step = mystack[top];
diamond[(last_step.sy + last_step.ty)/2][(last_step.sx + last_step.tx)/2] = '*';
diamond[last_step.sy][last_step.sx] = '*';
diamond[last_step.ty][last_step.tx] = '!';
nx = last_step.sx;
ny = last_step.sy;
ndir = last_step.dir + 1;
Left_diamond++;
}
else
{
cout<<"对不起，找不到答案！"<<endl;
break;
}
}
}

// 输出解
cout<<"下面是程序执行过程中棋子跳动的数据变化过程！"<<"\n";
for(int n=0; n<top; n++)
cout << "(" << mystack
.sx <<","<< mystack
.sy<<") ("<<mystack
.tx<< "," <<mystack
.ty<< ")" <<endl;

return 0;
}