poj1915 - Knight Moves

#include <iostream>
#include <cstring>
#include <cstdio>
#include <queue>
#include <cstdlib>

using namespace std;

struct node
{
int x, y, cost;
node(int x, int y, int cost):x(x), y(y), cost(cost){}
};

bool vis[300+5][300+5];
int n, T;

node st(0, 0, 0), ed(0, 0, 0);

const int dx[8] = {1, 2, 2, 1, -1, -2, -2, -1};
const int dy[8] = {2, 1, -1, -2, -2, -1, 1, 2};

inline bool check(int x, int y){
return (0<=x && x<n && 0<=y && y<n && !vis[x][y]);
}

int bfs(){
queue<node> q;
st.cost = 0;
q.push(st);
memset(vis, 0, sizeof(vis));
vis[st.x][st.y] = true;
while(!q.empty()){
node tmp = q.front(); q.pop();
if(tmp.x==ed.x && tmp.y==ed.y) return tmp.cost;
for(int i=0; i<8; ++i){
int tx = dx[i] + tmp.x;
int ty = dy[i] + tmp.y;
int tc = tmp.cost + 1;
if(check(tx, ty)){
q.push(node(tx, ty, tc));
vis[tx][ty] = true;
}
}
}
}

int main(){
scanf("%d", &T);
while(T--){
scanf("%d%d%d%d%d", &n, &st.x, &st.y, &ed.x, &ed.y);
printf("%d\n", bfs());
}
return 0;
}