ural 2029 Towers of Hanoi Strike Back (数学找规律)

 1 #include <climits>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cctype>
 5 #include <cmath>
 6 #include <ctime>
 7 #include <cstdlib>
 8 #include <cstdarg>
 9 #include <iostream>
10 #include <fstream>
11 #include <iomanip>
12 #include <sstream>
13 #include <exception>
14 #include <stdexcept>
15 #include <memory>
16 #include <locale>
17 #include <bitset>
18 #include <deque>
19 #include <list>
20 #include <map>
21 #include <set>
22 #include <queue>
23 #include <stack>
24 #include <vector>
25 #include <algorithm>
26 #include <iterator>
27 #include <functional>
28 #include <string>
29 #include <complex>
30 #include <valarray>
31 
32 using namespace std;
33 
34 typedef long long ll;
35 const int N = 55;
36 ll bit[N];
37 char s[N];
38 
39 inline void init() {
40     bit[0] = 1LL;
41     for(int i = 1; i < N; ++i) bit[i] = (bit[i-1] * 2LL);
42     return ;
43 }
44 
45 int n;
46 int pos, nxt;
47 
48 void solve(){
49     pos = nxt = 1;
50     ll ans = 0LL;
51     for(int i = n-1; i > -1; --i) {
52         int k = s[i] - ‘A‘ + 1; // A : 1 ; B : 2 ; C : 3;
53         if(k == nxt)  continue;
54         nxt = 6 - nxt - k, pos = k; // nxt 代表第i个盘子除当前位置柱子和目标柱子，剩下的那根
55 //printf("nxt = %d   pos = %d\n", nxt, pos);
56         ans += bit[i];
57     }
58     printf("%I64d\n", ans);
59     return ;
60 }
61 
62 int main()
63 {
64     init();
65 
66     while(~scanf("%d", &n)) {
67         scanf("%s", s);
68         solve();
69     }
70     return 0;
71 }