439:Knight Moves

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Knight Moves

BFS即可，字符串数组 size 定义成了 2 导致输入一直错误，应该是无法存入'\0' 引起的，待会儿再深究。

#include<bits/stdc++.h>
using namespace std;
const int maxn = 8;
typedef pair<int,int> P;
int d[maxn][maxn];
char a[3],b[3];
int x,y,x2,y2;
void BFS()
{
    queue<P>q;
    q.push(P(x,y));
    d[x][y] = 0;
    while(!q.empty()){
        P t = q.front(); q.pop();
        x = t.first,y = t.second;
        for(int dx = -2;dx <= 2;dx++){
            for(int dy = -2;dy <= 2;dy++){
                if(!dx || !dy) continue;
                if(abs(abs(dy)-abs(dx)) == 0) continue;
                if(x+dx >= 0 && x+dx < maxn && y+dy >= 0 && y+dy < maxn && d[x+dx][y+dy] == -1){
                    q.push(P(x+dx,y+dy));
                    d[x+dx][y+dy] = d[x][y] + 1;
                    if(x+dx == x2 && y+dy == y2) return;
                }
            }
        }
    }
}
int main()
{
    // freopen("data.in","r",stdin);
    // freopen("data.out","w",stdout);
    while(scanf("%s %s",a,b) == 2){
        memset(d,-1,sizeof(d));
        x = a[1] - '1';
        y = a[0] - 'a';
        x2 = b[1] - '1';
        y2 = b[0] - 'a';
        BFS();
        printf("To get from %s to %s takes %d knight moves.\n",a,b,d[x2][y2]);
    }
    return 0;
}