[백준 1547] 공 (Simulation) (C/C++)

#include <stdio.h>
#include <iostream>
#include <algorithm>
#include <string>
using namespace std;
 
string ball = "0123";
int N;
 
void swap(int cup1, int cup2)
{
    int cup1Idx, cup2Idx;
    
    for(int i = 1; i <= 3; i++)
    {
        if(ball[i] == (char)(cup1+'0'))
        {
            cup1Idx = i;
        }
        else if(ball[i] == (char)(cup2+'0'))
        {
            cup2Idx = i;
        }
    }
    
    char temp = ball[cup1Idx];
    ball[cup1Idx] = ball[cup2Idx];
    ball[cup2Idx] = temp;
}
    
int main(void)
{
//    freopen("B1547_input.txt", "r", stdin);
    
    cin >> N; 
    
    for(int i = 1; i <= N; i++)
    {
        int cup1, cup2;
        cin >> cup1 >> cup2;
        
        swap(cup1, cup2);
    }
    
    cout << ball[1];
    
    return 0;
}