[백준 1057] 토너먼트

[백준 1057] 토너먼트

문제 출처 : https://www.acmicpc.net/problem/1057

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Queue;
import java.util.StringTokenizer;
​
public class Problem1057 {
​
    public static void main(String[] args) throws NumberFormatException, IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        
        String str = br.readLine();
        StringTokenizer st = new StringTokenizer(str, " ");
        
        int num = Integer.parseInt(st.nextToken()); // 참가자 수
        int a = Integer.parseInt(st.nextToken()); // 김지민
        int b = Integer.parseInt(st.nextToken()); // 임한수
        
        ArrayList<Integer> arr = new ArrayList<Integer>();
        for (int i = 0; i < num; i++) {
            if(i == a-1 || i == b-1) arr.add(1);
            else arr.add(0);
        }
        
        
        Queue<Integer> q = new LinkedList<Integer>();
        int cnt = 0;
        boolean flag = true;
        
        while(arr.size() != 1) {
            
            cnt++;
            for (int i = 0; i < arr.size(); i+=2) {
                
                if(arr.size()%2==1 && i==arr.size()-1) { // 홀수일 때
                    q.add((arr.get(i)));
                    continue;
                }
                
                q.add((arr.get(i) | arr.get(i+1)));
                
                if(arr.get(i) == 1 && arr.get(i+1) == 1) {
                    flag = false;
                    break;
                }
            }
            
            if(!flag) break;
            
            int size = q.size();
            
            arr.clear();
            for (int i = 0; i < size; i++) {
                arr.add(q.poll());
            }
        }
        System.out.println(cnt);
    }
​
}