ZOJ 1091 BFS

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广搜，由于要记录步数，所以又用到了滚动队列。

一开始没判断起点和终点在一起的情况，WA了一次

#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#include <queue>using namespace std;char ss[3], dd[3];int map[9][9];int dx, dy;int point[8][2] = {{1, 2}, {1, -2}, {-1, -2}, {-1, 2}, {2, 1}, {2, -1}, {-2, 1}, {-2, -1}};int ans;struct Node {int xx, yy;Node() {}Node(int x, int y) {xx = x;yy = y;}};queue<Node> que[2];void bfs() {Node tmp = que[0].front();int a, b;a = 0, b = 1;int s1, s2;s1 = tmp.xx;s2 = tmp.yy;memset(map, 0, sizeof(map));map[s1][s2] = 1;while(!que[a].empty()) {swap(a, b);ans++;while(!que[b].empty()) {tmp = que[b].front();que[b].pop();int a1, a2;a1 = tmp.xx;a2 = tmp.yy;map[a1][a2] = 0;for(int i = 0; i < 8; i++) {int xx = a1 + point[i][0];int yy = a2 + point[i][1];if(xx == dx && yy == dy) {return;}else if(xx >= 1 && xx <= 8 && yy >= 1 && yy <= 8) {map[xx][yy] = 1;que[a].push(Node(xx, yy));}}}}}int main() {while(scanf("%s%s", ss, dd) != EOF) {int sx, sy;ans = 0;sx = ss[0] - 'a' + 1;sy = ss[1] - '0';dx = dd[0] - 'a' + 1;dy = dd[1] - '0';if(sx == dx && sy == dy) {printf("To get from %s to %s takes 0 knight moves.\n", ss, dd);continue;}while(!que[0].empty()) que[0].pop();while(!que[1].empty()) que[1].pop();que[0].push(Node(sx, sy));bfs();printf("To get from %s to %s takes %d knight moves.\n", ss, dd, ans);}return 0;}