POJ-2243（bfs）（Knight Moves ）

struct my
{
	int x, y;
} wo[100];
int main()
{
	char s[20];
	while (gets(s)) {
		int d[10][10] = {0};
		int g[10][10] = {0};
		int i, j;
		for (i = 1; i <= 8; ++i)
			for (j = 1; j <= 8; ++j)
				d[i][j] = 0x7fffffff;
		int a = s[0] - 'a' + 1;
		int b = s[1] - '0';
		int x = s[3] - 'a' + 1;
		int y = s[4] - '0';
		queue<my>q;
		my t;
		t.x = a;
		t.y = b;
		q.push(t);
		d[a][b] = 0;
		while (!q.empty()) {			
			my tx = q.front();
			g[tx.x][tx.y] = 1;
			if (tx.x == x && tx.y == y) {
				printf("To get from %c%c to %c%c takes %d knight moves.\n", s[0], s[1], s[3], s[4], d[x][y]);
				break;
			}
			q.pop();
			if (tx.x - 2 >= 1 && tx.y + 1 <= 8) {
				my ty;
				ty.x = tx.x - 2;
				ty.y = tx.y + 1;
				if (g[ty.x][ty.y] == 0) {
					if (d[ty.x][ty.y] > d[tx.x][tx.y] + 1)
						d[ty.x][ty.y] = d[tx.x][tx.y] + 1;
					q.push(ty);
				}
			}
			if (tx.x - 2 >= 1 && tx.y - 1 >= 1) {
				my ty;
				ty.x = tx.x - 2;
				ty.y = tx.y - 1;
				if (g[ty.x][ty.y] == 0) {
					if (d[ty.x][ty.y] > d[tx.x][tx.y] + 1)
						d[ty.x][ty.y] = d[tx.x][tx.y] + 1;
					q.push(ty);
				}
			}
			if (tx.x + 2 <= 8 && tx.y + 1 <= 8) {
				my ty;
				ty.x = tx.x + 2;
				ty.y = tx.y + 1;
				if (g[ty.x][ty.y] == 0) {
					if (d[ty.x][ty.y] > d[tx.x][tx.y] + 1)
						d[ty.x][ty.y] = d[tx.x][tx.y] + 1;
					q.push(ty);
				}
			}
			if (tx.x + 2 <= 8 && tx.y - 1 >= 1) {
				my ty;
				ty.x = tx.x + 2;
				ty.y = tx.y - 1;
				if (g[ty.x][ty.y] == 0) {
					if (d[ty.x][ty.y] > d[tx.x][tx.y] + 1)
						d[ty.x][ty.y] = d[tx.x][tx.y] + 1;
					q.push(ty);
				}
			}/////////////
			if (tx.x - 1 >= 1 && tx.y + 2 <= 8) {
				my ty;
				ty.x = tx.x - 1;
				ty.y = tx.y + 2;
				if (g[ty.x][ty.y] == 0) {
					if (d[ty.x][ty.y] > d[tx.x][tx.y] + 1)
						d[ty.x][ty.y] = d[tx.x][tx.y] + 1;
					q.push(ty);
				}
			}
			if (tx.x + 1 <= 8 && tx.y + 2 <= 8) {
				my ty;
				ty.x = tx.x + 1;
				ty.y = tx.y + 2;
				if (g[ty.x][ty.y] == 0) {
					if (d[ty.x][ty.y] > d[tx.x][tx.y] + 1)
						d[ty.x][ty.y] = d[tx.x][tx.y] + 1;
					q.push(ty);
				}
			}
			if (tx.x - 1 >= 1 && tx.y - 2 >= 1) {
				my ty;
				ty.x = tx.x - 1;
				ty.y = tx.y - 2;
				if (g[ty.x][ty.y] == 0) {
					if (d[ty.x][ty.y] > d[tx.x][tx.y] + 1)
						d[ty.x][ty.y] = d[tx.x][tx.y] + 1;
					q.push(ty);
				}
			}
			if (tx.x + 1 <= 8 && tx.y - 2 >= 1) {
				my ty;
				ty.x = tx.x + 1;
				ty.y = tx.y - 2;
				if (g[ty.x][ty.y] == 0) {
					if (d[ty.x][ty.y] > d[tx.x][tx.y] + 1)
						d[ty.x][ty.y] = d[tx.x][tx.y] + 1;
					q.push(ty);
				}
			}
		}
	}
	return 0;
}