From fecc57e4692b5d29e18ac81966b2c5283fea5dc3 Mon Sep 17 00:00:00 2001
From: monsileI <hansaem900d@kakao.com>
Date: Fri, 24 Jun 2022 17:43:30 +0900
Subject: [PATCH] combination

---
 .../src/test/combination_Algorithm.java       | 78 +++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 Basic_Of_Algorithm/src/test/combination_Algorithm.java

diff --git a/Basic_Of_Algorithm/src/test/combination_Algorithm.java b/Basic_Of_Algorithm/src/test/combination_Algorithm.java
new file mode 100644
index 0000000..59ce02d
--- /dev/null
+++ b/Basic_Of_Algorithm/src/test/combination_Algorithm.java
@@ -0,0 +1,78 @@
+package test;
+
+public class combination_Algorithm {
+
+public static void main(String[] args) {
+		
+		int [] arr = {1,2,3};
+		
+		boolean[]visited = new boolean[arr.length];
+		
+		combi(arr,visited);
+		
+		dfs(arr,visited,"");
+	
+		
+	}
+	
+
+	
+	static void dfs(int[]arr,boolean[]visited,String now) {
+		
+		System.out.println(now);
+		
+		if(now.length()==arr.length) return;
+		
+		for(int i=0;i<arr.length;i++) {
+			if(!visited[i]) {
+				visited[i] = true;
+				String newOne = now + arr[i];
+				dfs(arr,visited,newOne);
+				visited[i] = false;
+				
+			}
+			
+		}
+		
+	}
+	
+	static void combi(int[]arr,boolean[]visited) {
+		
+		
+		for(int i=1 ; i<=arr.length;i++) {
+			
+			System.out.println(arr.length+"중에 " + i + "개 뽑기");
+			
+			combination(arr,visited,i,0);
+			
+			System.out.println();
+		}
+		
+		
+		
+	}
+	static void combination(int[]arr,boolean[]visited,int r, int start) {
+		
+		if(r==0) {
+			print(visited,arr);
+			return;
+		}
+		
+		for(int i=start;i<arr.length;i++) {
+			visited[i] = true;
+			combination(arr,visited,r-1,i+1);
+			visited[i] = false;
+		}
+		
+		
+	}
+	static void print(boolean[]visited,int[]arr) {
+		String printNow = "";
+		for(int i=0;i<arr.length;i++) {
+			
+			if(visited[i]) printNow += arr[i];
+		}
+		System.out.println(printNow);
+	}
+
+}