[SOL] #148. 数字格子问题
说实话这题确实挺菜的。。。
废话少说，直接上代码^O^
Code:
1 #include <bits/stdc++.h> 2 using namespace std; 3 inline int read() { 4 int x = 0 , f = 1; char ch = getchar(); 5 for ( ; !isdigit(ch) ; ch = getchar()) if (ch == '-') f = -1; 6 for ( ; isdigit(ch) ; ch = getchar()) x = x * 10 + ch - '0'; 7 return x * f; 8 } 9 const int fac[] = {1 , 1 , 2 , 6 , 24 , 120 , 720 , 5040 , 40320 , 362880}; 10 const int aim = 24; 11 const int maxCon = 362880; 12 bool vis[maxCon]; 13 struct data { 14 int con[9]; 15 int hashVal; 16 int step; 17 }_begin; 18 queue <data> Q; 19 int Cantor(int s[]) { 20 int sum = 0; 21 for (int i = 1 ; i <= 8 ; i ++) { 22 int cnt = 0; 23 for (int j = i + 1 ; j <= 8 ; j ++) { 24 if (s[i] > s[j]) { 25 cnt ++; 26 } 27 } 28 sum += cnt * fac[8 - i]; 29 } 30 return sum + 1; 31 } 32 int bfs() { 33 Q.push(_begin); 34 while (Q.size()) { 35 data _top = Q.front(); Q.pop(); 36 37 if (vis[_top.hashVal]) { 38 continue; 39 } 40 if (_top.hashVal == aim) { 41 return _top.step; 42 } 43 vis[_top.hashVal] = true; 44 _top.step ++; 45 data _next = _top; 46 for (int i = 1 ; i <= 4 ; i ++) { 47 swap(_next.con[i] , _next.con[i + 4]); 48 } 49 _next.hashVal = Cantor(_next.con); 50 Q.push(_next); 51 _next = _top; 52 int _up = _next.con[4] , _dwn = _next.con[8]; 53 for (int i = 4 ; i >= 2 ; i --) { 54 _next.con[i] = _next.con[i - 1]; 55 _next.con[i + 4] = _next.con[i + 3]; 56 } 57 _next.con[1] = _up; 58 _next.con[5] = _dwn; 59 _next.hashVal = Cantor(_next.con); 60 Q.push(_next); 61 _next = _top; 62 int two = _next.con[2] , three = _next.con[3] , seven = _next.con[7] , six = _next.con[6]; 63 _next.con[2] = six , _next.con[3] = two , _next.con[7] = three , _next.con[6] = seven; 64 _next.hashVal = Cantor(_next.con); 65 Q.push(_next); 66 } 67 } 68 69 int main() { 70 for (int i = 1 ; i <= 8 ; i ++) { 71 _begin.con[i] = read(); 72 } 73 _begin.hashVal = Cantor(_begin.con); 74 printf("%d\n" , bfs()); 75 }
