poj1915

简单题

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <queue>
using namespace std;

struct XPoint
{
    int x, y;
    int step;

} s, e;

#define maxn 306

int n;
bool vis[maxn][maxn];
int dir[8][2] =
{
{ 1, 2 },
{ 2, 1 },
{ -1, 2 },
{ -2, 1 },
{ -1, -2 },
{ -2, -1 },
{ 1, -2 },
{ 2, -1 } };

bool ok(XPoint &b)
{
    if (b.x < 0 || b.y < 0 || b.x >= n || b.y >= n)
        return false;
    return !vis[b.x][b.y];
}

void bfs()
{
    queue<XPoint> q;
    s.step = 0;
    q.push(s);
    memset(vis, 0, sizeof(vis));
    vis[s.x][s.y] = true;
    while (!q.empty())
    {
        XPoint a = q.front();
        q.pop();
        for (int i = 0; i < 8; i++)
        {
            XPoint b;
            b.x = a.x + dir[i][0];
            b.y = a.y + dir[i][1];
            b.step = a.step + 1;
            if (ok(b))
            {
                vis[b.x][b.y] = true;
                q.push(b);
            }
            if (b.x == e.x && b.y == e.y)
            {
                printf("%d\n", b.step);
                return;
            }
        }
    }
}

int main()
{
//    freopen("t.txt", "r", stdin);
    int t;
    scanf("%d", &t);
    while (t--)
    {
        scanf("%d", &n);
        scanf("%d%d", &s.x, &s.y);
        scanf("%d%d", &e.x, &e.y);
        if (s.x == e.x && s.y == e.y)
        {
            printf("0\n");
            continue;
        }
        bfs();
    }
    return 0;
}