diff --git a/Basic_Of_Algorithm/src/test/color.java b/Basic_Of_Algorithm/src/test/color.java
new file mode 100644
index 0000000..52513e6
--- /dev/null
+++ b/Basic_Of_Algorithm/src/test/color.java
@@ -0,0 +1,81 @@
+package test;
+
+public class color {
+
+	public static void main(String[] args) {
+		
+		String[]temp = {"RRRBB", 
+				"GGBBB", 
+				"BBBRR",  
+				"BBRRR", 
+				"RRRRR"};
+		
+		char[][]map = new char[temp.length][temp[0].length()];
+		
+		
+		for(int i=0;i<map.length;i++) {
+			for(int j=0;j<map[0].length;j++) {
+				map[i][j] = temp[i].charAt(j);
+			}
+		}
+		
+		boolean[][]visited = new boolean[map.length][map[0].length];
+		boolean[][]visited2 = new boolean[map.length][map[0].length];
+		
+		int normal = 0;
+		
+		for(int i=0;i<map.length;i++) {
+			for(int j=0;j<map[0].length;j++) {
+				if(!visited[i][j]) {
+					dfs(i,j,map,visited);
+					normal++;
+				}
+			}
+		}
+		
+		
+		int disabled = 0;
+		
+		for(int i=0;i<map.length;i++) {
+			for(int j=0;j<map[0].length;j++) {
+				if(map[i][j]=='G') map[i][j] = 'R';
+				
+			}
+		}
+		
+		for(int i=0;i<map.length;i++) {
+			for(int j=0;j<map[0].length;j++) {
+				if(!visited2[i][j]) {
+					dfs(i,j,map,visited2);
+					disabled++;
+				}
+			}
+		}
+		
+		System.out.println(normal);
+		System.out.println(disabled);
+	}
+	
+	static void dfs(int i,int j,char[][]map,boolean[][]visited) {
+		
+		int[][]move = {{0,1},{1,0},{0,-1},{-1,0}};
+		
+		visited[i][j] = true;
+		
+		
+		for(int d=0;d<4;d++) {
+			
+			int newI = i + move[d][0];
+			int newJ = j + move[d][1];
+			
+			if(newI<0||newJ<0||map.length-1<newI||map[0].length-1<newJ) continue;
+			
+			if(!visited[newI][newJ] && map[newI][newJ]==map[i][j]) {
+				dfs(newI,newJ,map,visited);
+			}
+			
+		}
+		
+		
+	}
+}
diff --git a/Basic_Of_Algorithm/src/test/dfs.java b/Basic_Of_Algorithm/src/test/dfs.java
new file mode 100644
index 0000000..3da9ff7
--- /dev/null
+++ b/Basic_Of_Algorithm/src/test/dfs.java
@@ -0,0 +1,57 @@
+package test;
+
+public class dfs {
+
+	static int answer = Integer.MAX_VALUE;
+	
+	static String t;
+	static boolean[] visited;
+	
+	public static void main(String[] args) {
+		
+		
+		String begin = "hit";
+		String target = "cog";
+		String [] words = {"hot", "dot", "dog", "lot", "log", "cog"};
+		
+		
+		
+		t = target;
+		
+		visited = new boolean[words.length];
+		
+		dfs(begin,words,0);
+		
+		System.out.println(answer);
+		
+		
+	}
+	
+	static void dfs(String begin, String [] words , int count) {
+		
+		if(begin.equals(t)) {
+			System.out.println(begin + " : " + count);
+			answer = Math.min(answer, count);
+			return;
+		}
+		
+		
+		for(int i=0;i<words.length;i++) {
+			int c = 0;
+			for(int j=0;j<begin.length();j++) {
+				if(words[i].charAt(j)!=begin.charAt(j)) {
+					c++;
+				}
+			}
+			
+			
+			if(!visited[i] && c==1) {
+				visited[i]= true;
+				begin = words[i];
+				dfs(begin,words,count+1);
+				visited[i] = false;
+			}
+		}
+		
+	}
+}
diff --git a/Basic_Of_Algorithm/src/test/network.java b/Basic_Of_Algorithm/src/test/network.java
new file mode 100644
index 0000000..2132cfc
--- /dev/null
+++ b/Basic_Of_Algorithm/src/test/network.java
@@ -0,0 +1,38 @@
+package test;
+
+import java.util.*;
+
+public class network {
+	
+	public static void main(String[] args) {
+		
+		int n = 3;
+		
+		int[][]computers = {{1,1,0},{1,1,0},{0,0,1}};
+		
+		int answer = 0;
+		
+		boolean[]visited = new boolean[computers.length];
+		
+		
+		for(int i=0;i<computers.length;i++) {
+			if(!visited[i]) {
+				answer++;
+				dfs(i,visited,computers);
+			}
+		}
+		
+		System.out.println(answer);
+		
+	}
+	static void dfs(int node,boolean[]visited,int[][]computers) {
+		visited[node] = true;
+		
+		for(int i=0;i<computers.length;i++) {
+			if(!visited[i] && computers[node][i]==1) {
+				dfs(i,visited,computers);
+			}
+		}
+	}
+
+}
diff --git a/Basic_Of_Algorithm/src/test/network2.java b/Basic_Of_Algorithm/src/test/network2.java
new file mode 100644
index 0000000..895d7a6
--- /dev/null
+++ b/Basic_Of_Algorithm/src/test/network2.java
@@ -0,0 +1,39 @@
+package test;
+
+import java.util.*;
+
+public class network2 {
+	
+	public static void main(String[] args) {
+		
+		int n = 3;
+		
+		int[][]computers = {{1,1,0},{1,1,0},{0,0,1}};
+		
+		int answer = 0;
+		
+		boolean[]visited = new boolean[computers.length];
+		
+		for(int i=0;i<computers.length;i++) {
+			if(!visited[i]) {
+				dfs(i,visited,computers);
+				answer++;
+			}
+		}
+		
+		System.out.println(answer);
+	}
+	static void dfs(int node,boolean[]visited,int[][]computers) {
+		
+		visited[node] = true;
+		
+		for(int i=0;i<computers.length;i++) {
+			
+			if(!visited[i] && computers[node][i]==1) {
+				dfs(i,visited,computers);
+			}
+			
+		}
+		
+	}
+}