439UVa骑士移动

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visit数组不能用有多余的行列

#include<stdio.h>#include<string.h>const int MAXN = 8;int visit[MAXN][MAXN];int dist[MAXN][MAXN];int q[MAXN*MAXN];int dx[8]={-2,-2,-1,-1,+1,+1,+2,+2};int dy[8]={-1,+1,-2,+2,-2,+2,-1,+1};int bfs(int i,int j,int ii,int jj);int main(){//freopen("input.txt","r",stdin);char s1[5];char s2[5];while(scanf("%s%s",s1,s2)==2){int sr = s1[1]-'1';int sc = s1[0]-'a';int er = s2[1]-'1';int ec = s2[0]-'a';memset(visit,0,sizeof(visit));int dis = bfs(sr,sc,er,ec);printf("To get from %s to %s takes %d knight moves.\n",s1,s2,dis);}}int bfs(int i,int j,int ii,int jj){int front = 0;int rear = 0;int u=i*MAXN+j;q[rear++] = u;visit[i][j] = 1;dist[i][j] = 0;if(i == ii && j==jj)    return dist[i][j];while(front<rear){u = q[front++];i = u/MAXN;j = u%MAXN;for(int d = 0; d < 8;d++){int ni = i + dx[d];int nj = j + dy[d];if(ni>=0&&ni<MAXN&&nj>=0&&nj<MAXN&&!visit[ni][nj])  //此处ni,nj上限必须为实际行列数{q[rear++] = ni*MAXN+nj;visit[ni][nj] = 1;dist[ni][nj] = dist[i][j]+1;if(ni == ii && nj==jj)return dist[ni][nj];}}}}

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