## Sicily 1150. 简单魔板

BFS。军训晚上下雨无聊写的水题。

 1 #include <iostream>
2 #include <cstdio>
3 #include <algorithm>
4 #include <cstring>
5 #include <queue>
6 #include <vector>
7 #define rep(i,l,r) for(int i = l; i <= r; i++)
8 #define clr(x,y) memset(x,y,sizeof(x))
9 #define travel(x) for(Edge *p = last[x]; p; p = p -> pre)
10 using namespace std;
12     int ans = 0, f = 1; char c = getchar();
13     for(; !isdigit(c); c = getchar()) if (c == '-') f = -1;
14     for(; isdigit(c); c = getchar()) ans = ans * 10 + c - '0';
15     return ans * f;
16 }
17 int N, n, target;
18 struct Node{
19     int num; vector <char> path;
20 };
21 queue <Node> q;
22 inline int A(int x){
23     int h = x / 10000; int l = x % 10000;
24     return l * 10000 + h;
25 }
26 inline int B(int x){
27     int h = x / 10000; int l = x % 10000;
28     int hh = h / 10; int hl = h % 10;
29     int lh = l / 10; int ll = l % 10;
30     return hl * 10000000 + hh * 10000 + ll * 1000 + lh;
31 }
32 inline int C(int x){
33     int t[9]; rep(i,1,8){
34         t[8 - i + 1] = x % 10;
35         x = x / 10;
36     }
37     return t[1] * 1e7 + t[6] * 1e6 + t[2] * 1e5 + t[4] * 1e4 + t[5] * 1e3 + t[7] * 1e2 + t[3] * 10 + t[8];
38 }
39 Node bfs(){
40     while (!q.empty()) q.pop();
41     Node s; s.num = 12348765;
42     q.push(s);
43     while (!q.empty()){
44         Node now = q.front(); q.pop();
45         if (now.path.size() > N) return now;
46         else{
47             Node fun1 = now;
48             fun1.num = A(fun1.num);
49             fun1.path.push_back('A');
50             if (fun1.num == target) return fun1;
51             else q.push(fun1);
52             Node fun2 = now;
53             fun2.num = B(fun2.num);
54             fun2.path.push_back('B');
55             if (fun2.num == target) return fun2;
56             else q.push(fun2);
57             Node fun3 = now;
58             fun3.num = C(fun3.num);
59             fun3.path.push_back('C');
60             if (fun3.num == target) return fun3;
61             else q.push(fun3);
62         }
63     }
64 }
65 void work(){
66     target = 0;
67     rep(i,1,8){
68         int x = read(); target = target * 10 + x;
69     }
70     Node out = bfs(); int cnt = out.path.size();
71     if (cnt > N) printf("-1\n");
72     else{
73         printf("%d ",cnt);
74         rep(i,0,cnt - 1) printf("%c",out.path[i]);
75         printf("\n");
76     }
77 }
78 int main(){
84 }