UVa 439骑士的移动（BFS）

https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=380

做了这道题之后对BFS总算是有了点认识了。

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

int map[10][10];
typedef struct node
{
    int x, y, z;
    node(int a, int b, int c)  { x = a; y = b; z = c; }
    node() {}
}queue;

queue q[100];

int d[8][2] = { { 2, 1 }, { 2, -1 }, { -2, -1 }, { -2, 1 }, { 1, 2 }, { 1, -2 }, { -1, 2 }, { -1, -2 } };
int bfs(int x1, int y1, int x2, int y2)
{
    int move = 0, number = 1;
    if (x1 == x2 && y1 == y2)  return 0;
    memset(map, 0, sizeof(map));
    q[0] = node(x1, y1, 0);
    while (move < number)
    {
        queue p = q[move++];
        for (int k = 0; k < 8; k++)
        {
            int xx = p.x + d[k][0];
            int yy= p.y + d[k][1];
            if (xx == x2 && yy == y2)  return p.z + 1;
            if (!map[xx][yy] && xx>0 && xx<9 && yy>0 && yy < 9)
            {
                map[xx][yy] = 1;
                q[number++] = node(xx, yy, p.z + 1);
            }
        }
    }
}

int main()
{
    char s1, s2;
    int x1, x2, y1, y2;
    while (cin >> s1 >> y1 >> s2 >> y2)
    {
        x1 = (int)(s1 - 'a' + 1);
        x2 = (int)(s2 - 'a' + 1);
        int x=bfs(x1, y1, x2, y2);
        cout << "To get from "<<s1<<y1<< " to " <<s2<<y2<< " takes "<<x <<" knight moves."<< endl;
    }
    return 0;
}