[SW Expert Academy] 그래프의 삼각형 (D3)

https://swexpertacademy.com/main/code/problem/problemDetail.do?contestProbId=AWbHcWd6AFcDFAV0&categoryId=AWbHcWd6AFcDFAV0&categoryType=CODE&problemTitle=%EA%B7%B8%EB%9E%98%ED%94%84%EC%9D%98+%EC%82%BC%EA%B0%81%ED%98%95&orderBy=FIRST_REG_DATETIME&selectCodeLang=ALL&select-1=&pageSize=10&pageIndex=1

SW Expert Academy

 

 

인접 리스트

import java.util.ArrayList;
import java.util.Scanner;

class Solution {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int t = sc.nextInt();
		
		for(int tc=1;tc<=t;tc++) {
			int n = sc.nextInt();
			int m = sc.nextInt();
			
			ArrayList<Integer>list[]=new ArrayList[n+1];
			
			for(int i=1;i<n+1;i++) {
				list[i] = new ArrayList<>();
			}
			
			for(int i=0;i<m;i++) {
				int x = sc.nextInt();
				int y = sc.nextInt();
				list[x].add(y);
				list[y].add(x);
			}
			
			int cnt=0;
			
			for(int i=1;i<n+1;i++) {
				for(int j:list[i]) {
					for(int k:list[j]) {
						if(i<j&&j<k&&list[k].contains(i)) {
							cnt++;
						}
					}
				}
			}
			
			System.out.println("#"+tc+" "+cnt);
			
			
		}
	}
}

 

 

인접 행렬

import java.util.Scanner;

class Solution {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int t = sc.nextInt();

		for (int tc = 1; tc <= t; tc++) {
			int n = sc.nextInt();
			int m = sc.nextInt();

			int arr[][] = new int[n + 1][n + 1];

			for (int i = 0; i < m; i++) {
				int x = sc.nextInt();
				int y = sc.nextInt();

				arr[x][y] = arr[y][x] = 1;
			}

			int ans = 0;

			for (int i = 1; i < n + 1 - 2; i++) {
				for (int j = i + 1; j < n + 1 - 1; j++) {
					if(arr[i][j]==0) continue;
					for (int k = j + 1; k < n + 1; k++) {
						if(arr[j][k]==0) continue;
						if (i<j && arr[k][i] == 1) {
							ans++;
						}
					}
				}
			}

			System.out.println("#" + tc + " " + ans);

		}
	}
}