[C] 백준 - 12015번: 가장 긴 증가하는 부분 수열 2

6월 5일(수) - 이분 탐색(12015번)

https://www.acmicpc.net/problem/12015

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최초 생각 정리

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문제점

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풀이 - 1

(C언어 풀이)

(풀이출처 -> )

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풀이 - 2

(java 풀이)

(풀이출처 -> https://st-lab.tistory.com/285)

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

import java.util.*;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        int N = Integer.parseInt(br.readLine());

        int[] arr = new int[N];
        int[] LIS = new int[N];

        StringTokenizer st = new StringTokenizer(br.readLine());

        for(int i=0; i<N; i++)
        {
            arr[i] = Integer.parseInt(st.nextToken());
        }

        LIS[0] = arr[0];
        int length_of_LIS = 1;

        for(int i=1; i<N; i++)
        {
            int key = arr[i];

            if(LIS[length_of_LIS - 1] < key)
            {
                length_of_LIS++;
                LIS[length_of_LIS - 1] = key;
            }
            else
            {
                int left = 0;
                int right = length_of_LIS;

                while (left < right)
                {
                    int mid = (left + right)/2;

                    if(LIS[mid] < key)
                    {
                        left = mid +1 ;
                    }
                    else
                    {
                        right = mid;
                    }
                }

                LIS[left] = key;
            }
        }

        System.out.println(length_of_LIS);
    }
}

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