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
    
     using namespace std;const int maxn = 8;typedef pair
     
       P;int d[maxn][maxn];char a[3],b[3];int x,y,x2,y2;void BFS(){    queue
      
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;}