bj7570(줄 세우기) - 그리디

 

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    static int N;
    static int[] arr;
    static StringTokenizer stringTokenizer;
    static BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
    public static void main(String[] args) throws IOException {
        initialize();
        System.out.println(N - getAnswer());
    }

    private static int getAnswer() {
        int max = 1;
        int cnt = 0;
        for(int i = 1; i <= N; i++){
            if(arr[i] > arr[i-1]){
                cnt++;
                if(cnt > max)
                    max = cnt;
            }else{
                cnt = 1;
            }
        }
        return max;
    }

    private static void initialize() throws IOException {
        N = Integer.parseInt(bufferedReader.readLine());
        arr = new int[N+1];
        stringTokenizer = new StringTokenizer(bufferedReader.readLine());
        for(int i = 0; i < N; i++){
            arr[Integer.parseInt(stringTokenizer.nextToken())] = i;
        }
    }
}

 

개어렵네;;