2024.05.21 ( Java )

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1. 스택수열

Stack ( https://www.acmicpc.net/problem/1874 )

GitHub -> https://github.com/changi123/Algorithm-And-Data_structure/blob/main/Algorithm/src/problem_solving/stack/BaekJoon_1874.java

package problem_solving.stack;

import java.util.Scanner;
import java.util.Stack;

public class BaekJoon_1874 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = Integer.parseInt(sc.next());
		Stack<Integer> st = new Stack();
		int start = 0 ; 
		StringBuilder sb = new StringBuilder();
		while(n-- > 0) {
			int num = Integer.parseInt(sc.next());
			if( num > start ) {				
				for(int i= start+1  ;  i<= num ; i++) {
					st.push(i);
					sb.append("+"+'\n');
				}
				start = num ;
			}
			
			if( st.peek() != num ) {
				System.out.println("NO");
				return ;
			}else {
				st.pop();
				sb.append("-"+'\n');
			}
			
		}
		System.out.println(sb);
	}

}

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2. 제로

Stack ( https://www.acmicpc.net/problem/10773 )

GitHub - > https://github.com/changi123/Algorithm-And-Data_structure/blob/main/Algorithm/src/problem_solving/stack/BaekJoon_10773.java

package problem_solving.stack;

import java.util.Scanner;
import java.util.Stack;

public class BaekJoon_10773 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = Integer.parseInt(sc.next());
		Stack<Integer> st = new Stack();
		long sum = 0 ;
		for(int i= 0 ; i < n ; i++) {
			int num = Integer.parseInt(sc.next());
			if( num !=0 ) {
				st.push(num);
			}else {
				st.pop();
			}
		}
		
		while(!st.isEmpty()) {
			sum+=st.pop();
		}
		System.out.println(sum);
		
		
	}

}

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3. 단어순서 뒤집기

Stack ( https://www.acmicpc.net/problem/12605 )

GitHub -> https://github.com/changi123/Algorithm-And-Data_structure/blob/main/Algorithm/src/problem_solving/stack/BaekJoon_12605.java

package problem_solving.stack;

import java.util.Arrays;
import java.util.Scanner;

public class BaekJoon_12605 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = Integer.parseInt(sc.next());
		sc.nextLine();
		
		for(int i = 0 ; i < n; i ++) {
			StringBuilder sb= new StringBuilder("Case #"+(i+1)+": ");
			String s = sc.nextLine();
			String[] arr = s.split(" ");
			for(int j = arr.length-1 ;  j >= 0 ; j--) {
				sb.append(arr[j]+ " ");
			}
			System.out.println(sb.toString());
		}
	}

}

4. 막대기

Stack ( https://www.acmicpc.net/problem/17608 )

GitHub -> https://github.com/changi123/Algorithm-And-Data_structure/blob/main/Algorithm/src/problem_solving/stack/BaekJoon_17608.java

package problem_solving.stack;

import java.util.Scanner;
import java.util.Stack;

public class BaekJoon_17608 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = Integer.parseInt(sc.next());
		Stack<Integer> st = new Stack();
		for(int i= 0 ; i < n ; i++) {
			int num = Integer.parseInt(sc.next());
			st.push(num);
		}
		int cnt = 0 ;
		int last = st.pop();
		int temp = last ;
		int i= 0 ;
		while(!st.isEmpty()) {
			if(st.peek() > last && st.peek() > temp) {
				temp = st.peek();
				st.pop();
				cnt++;	
			}else {
				st.pop();
			}
			
		}
		
		System.out.println(cnt+1);
		
	}

}

5. 민균이의 비밀번호

Hash ( https://www.acmicpc.net/problem/9933 )

GitHub -> https://github.com/changi123/Algorithm-And-Data_structure/blob/main/Algorithm/src/problem_solving/hash/BaekJoon_9933.java

package problem_solving.hash;

import java.util.HashSet;
import java.util.Scanner;

public class BaekJoon_9933 {

	public static void main(String[] args) {
		Scanner sc= new Scanner(System.in);
		int n = Integer.parseInt(sc.next());
		HashSet<String> hs = new HashSet();
		int size = hs.size();
		for(int i= 0 ; i < n ; i++) {
			StringBuilder sb = new StringBuilder(sc.next());
			if( sb.toString().equals(sb.reverse().toString())) {
				System.out.print(sb.length()+" "+sb.charAt(sb.length()/2));
				return ; 
			}
			
			hs.add(sb.toString());
			hs.add(sb.reverse().toString());
			if( size == hs.size()) {
				System.out.print(sb.length()+" "+sb.charAt(sb.length()/2));
				return ; 
			}else {
				size = hs.size();
			}
		}
		
		
		
	}

}

6. 할리갈리

Hash ( https://www.acmicpc.net/problem/27160 )

GitHub -> https://github.com/changi123/Algorithm-And-Data_structure/blob/main/Algorithm/src/problem_solving/hash/BaekJoon_27160.java

7. 숫자 카드 2

Hash ( https://www.acmicpc.net/problem/108160 )

GitHub -> https://github.com/changi123/Algorithm-And-Data_structure/blob/main/Algorithm/src/problem_solving/hash/BaekJoon_10816.java

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Silver 1 65% -> Silver 1 92%

Stack - 4문제

Hash - 3문제