Create L13-1.cpp

L13-1.cpp

@@ -0,0 +1,51 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+typedef long long ll;
+typedef pair<ll, ll> pl;
+
+#define PUB push_back
+#define fi first
+#define se second
+
+int N, ans = 0;
+string S, fin = "";
+char trans[4][4] =  {{'A', 'B', 'C', 'D'},
+				  {'B', 'A', 'D', 'C'},
+				  {'C', 'D', 'A', 'B'},
+				  {'D', 'C', 'B', 'A'}};
+
+string ubah(string &a, int thn){
+	string ret = a;
+
+	for(int i=0;i<N;i++){
+		int nxt = (i+thn) % N;
+		ret[i] = trans[a[i]-'A'][a[nxt]-'A'];
+	}
+
+	return ret;
+}
+
+int main(){
+	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
+
+	cin >> S;
+	N = S.length();
+	for(int i=0;i<N;i++) fin += "A";
+
+	for(int i=21;i>=0;i--){
+		string now = ubah(S, (1 << i));
+		if(now != fin){
+			if(i == 21){
+				cout << -1 << endl;
+				return 0;
+			}
+
+			ans += (1 << i);
+			S = now;	
+		}
+	}
+
+	if(S == fin) cout << 0 << endl;
+	else cout << ans + 1 << endl;
+}