【題解】ZeroJudge b190: 97七區資訊學科5(改編)

#include <iostream>
#include <cmath>
using namespace std;

int times, todo, doing;

void move(int now, char start, char target, char between){
    if (now > 0){
        move(now-1, start, between, target);
        cout << "ring " << now << " : " << start << " -> " << target << "\n";
        times++;
        move(now-1, between, target, start);
    }
}

int main(){
    int n;
    char start, between, target, temp;
    while (cin >> n){
        times = 0;
        todo = n;
        doing = n;
        start = 'a';
        if (n % 2 == 0){
            target = 'c';
            between = 'b';
        }else{
            target = 'b';
            between = 'c';
        }
        while (todo > 0){
            //move the pile above doing
            move(doing-1, start, between, target);
            if (doing-1 > 0) todo -= 1;
            if (todo == 0) break;
            
            //move doing
            cout << "ring " << doing << " : " << start << " -> " << target << "\n";
            times++;
            todo -= 1;
            if (todo == 0) break;
            
            //setting for the second part
            doing -= 2;
            temp = between;
            between = start;
            start = temp;
            
            //move second pile (do not todo-=1)
            move(doing-1, start, between, target);
            
            //move doing again
            cout << "ring " << doing << " : " << start << " -> " << target << "\n";
            times++;
            todo -= 1;
            if (todo == 0) break;
            
            //setting for the next round
            doing -= 1;
            temp = start;
            start = between;
            between = target;
            target = temp;
        }
        cout << "共移動了 " << times << " 步\n";
    }
}