uva 439 bfs 广搜

#include <cstdio>
#include <iostream>
#include <string>
#include <algorithm>
#include <cctype>
#include <queue>
#include <cstring>
using namespace std;

int vis[100][100];
int dis[100][100];
int dx[8] = {1,2,2,1,-1,-2,-2,-1};
int dy[8] = {-2,-1,1,2,2,1,-1,-2};
int x[4];

typedef struct node{
	int x, y;
}node;

queue<node> que;

bool judge(int x, int y)
{
	if(x >= 1 && x <= 8 && y >= 1 && y <= 8)
		return true;
	else
		return false;
}

void bfs()
{
	memset(vis, 0, sizeof(vis));
	memset(dis, 0, sizeof(dis));
	node start;
	start.x = x[0];
	start.y = x[1];
	vis[x[0]][x[1]] = 1;
	while(!que.empty())
		que.pop();
	que.push(start);
	while(!que.empty())
	{
		node front = que.front();
		que.pop();
		for(int i = 0; i < 8; i++)
		{
			int xx = front.x + dx[i];
			int y = front.y + dy[i];
			if(judge(xx, y) && !vis[xx][y])
			{
				node neww;
				neww.x = xx;
				neww.y = y;
				vis[xx][y] = 1;
				dis[xx][y] = dis[front.x][front.y] + 1;
				if(xx == x[2] && y == x[3])
					return ;
				que.push(neww);
			}
		}
	}
}
		
int main()
{
	//freopen("ztest.txt","r",stdin);
	string str;
	while(getline(cin, str))
	{
		int u = 0;
		for(int i = 0; i< str.size(); i++)
		{
			if(str[i] != ' ')
			{
				if(isalpha(str[i]))
					x[u++] = str[i]-'a'+1;
				else
					x[u++] = str[i]-'0';
			}
		}
		bfs();
		printf("To get from %c%d to %c%d takes %d knight moves.\n",x[0]+'a'-1,x[1],x[2]+'a'-1,x[3],dis[x[2]][x[3]]);
	}
	return 0;
}