Submission #381143

#	Time	Username	Problem	Language	Result	Execution time	Memory
381143		vijay	Triumphal arch (POI13_luk)	Java	0 / 100	2060 ms	75412 KiB

luk

import java.io.*;
import java.util.*;

public class luk {
    static int N;
    static int[] dayCount;
    static ArrayList<Integer>[] adj;
    public static void main(String[] args) throws IOException, FileNotFoundException {
        Scanner in = new Scanner(System.in);
        // PrintWriter out = new PrintWriter("luk.out");

        N = in.nextInt();
        dayCount = new int[N];
        adj = new ArrayList[N];

        for(int i = 0; i < N; i++){
            adj[i] = new ArrayList<>(); 
        }

        for(int i = 0; i < N - 1; i++){
            int a = in.nextInt() - 1;
            int b = in.nextInt() - 1;
            adj[a].add(b);
            adj[b].add(a);
        }

        recurse(0, 0, -1);

        // System.out.println(Arrays.toString(dayCount));
        
        // System.out.println(works(2));
        int a = 0;
        int b = N - 1;
        while(a != b){
            int mid = (a + b)/2;
            if(works(mid)){
                b = mid;
            } else {
                a = mid + 1;
            }
        }

        System.out.println(a);
    }

    static boolean works(int count){
        int[] at = new int[count];
        int pos = 0;
        for(int dayPos = 1; dayPos < N; dayPos++){
            for(int city = 0; city < dayCount[dayPos]; city++){
                if(at[pos] >= dayPos){
                    return false;
                }
                at[pos]++;
                pos++;
                pos%=count;
            }
        }

        return true;
    }

    static void recurse(int position, int day, int prev){
        dayCount[day]++;
        for(int ap: adj[position]){
            if(ap != prev){
                recurse(ap, day + 1, position);
            }
        }
    }
}

Compilation message (stderr)

Note: luk.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

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