经典跳马问题

我的代码：

#include <cstdio>
using namespace std;
int n,m,ans = 0;
struct Point
{
	int x,y;
} a[10005];
bool used[15][15];
int dx[4] = {1,1,2,2};
int dy[4] = {2,-2,1,-1};
void print(int k)
{
	printf("<%d>(0,0)",ans);
	for (int i = 1;i <= k;i++)
	{
		printf("-(%d,%d)",a[i].x,a[i].y);
	}
	printf("\n");
}
void dfs(int x,int y,int num)
{
	if (x == n && y == m)
	{
		ans++;
		print(num-1);
		return;
	}
	for (int i = 0;i < 4;i++)
	{
		int ux = x+dx[i],uy = y+dy[i];
		if (ux < 0 || uy < 0 || ux > n || uy > m) continue;
		if (used[ux][uy]) continue;
		used[ux][uy] = 1;
		a[num] = (Point){ux,uy};
		dfs(ux,uy,num+1);
		used[ux][uy] = 0; 
	}
}
int main()
{
	scanf("%d%d",&n,&m);
	used[0][0] = 1;
	dfs(0,0,1);
	printf("%d\n",ans);
	return 0;
}