diff --git a/KJE/BJ1085.cpp b/KJE/BJ1085.cpp
new file mode 100644
index 0000000..b59560c
--- /dev/null
+++ b/KJE/BJ1085.cpp
@@ -0,0 +1,37 @@
+#include <iostream>
+using namespace std;
+int main(){
+    int x,y,w,h;
+    cin>>x>>y>>w>>h;
+    int tmp;
+
+    if(x>y){
+        tmp=y;
+    }
+    else{
+        tmp=x;
+    }
+
+    if(w-x>h-y){
+        if(h-y>tmp){
+            cout<<tmp;
+        }
+        else{
+        cout<<h-y;
+        }
+
+        }
+
+    else{
+
+        if(w-x>tmp){
+            cout<tmp;
+        }
+        else{
+        cout<<w-x;
+        }
+
+    }
+
+    return 0;
+}
diff --git a/KJE/BJ1181.cpp b/KJE/BJ1181.cpp
new file mode 100644
index 0000000..e69de29
diff --git a/KJE/BJ13116.cpp b/KJE/BJ13116.cpp
new file mode 100644
index 0000000..1b01c14
--- /dev/null
+++ b/KJE/BJ13116.cpp
@@ -0,0 +1,26 @@
+#include <iostream>
+using namespace std;
+//공통된 부모노드를 찾아라
+
+int main(){
+    int T,a,b;
+    cin>>T;
+    for(int i=0;i<T;i++){
+        cin>>a>>b;
+    }
+    while(a!=b){
+        if(a>b){
+            a=a/2;
+        }
+        else if(a<b){
+            b=b/2;
+        }
+        else{
+            a=a/2;
+            b=b/2;
+        } 
+        cout<<a*10<<endl;  //b*10 해도 된다
+
+    }
+
+}
\ No newline at end of file
diff --git a/KJE/BJ9372.cpp b/KJE/BJ9372.cpp
new file mode 100644
index 0000000..98b919a
--- /dev/null
+++ b/KJE/BJ9372.cpp
@@ -0,0 +1,19 @@
+#include <iostream>
+#include <string.h>
+using namespace std;
+
+//예제를 보니까 국가마다 다 이어져 있음
+int main(){
+    int T,N,M,a,b;
+    cin>>T;
+    while(T--){
+        cin>>N>>M;  //국가의 수, 비행기의 종류
+        for(int i=0;i<M;i++){
+            cin>>a>>b;
+        }
+        cout<<N-1<<endl;
+    }
+//너무 단순한데 이게 맞나요..
+
+    return 0;
+}
\ No newline at end of file
diff --git a/KJE/Tree.cpp b/KJE/Tree.cpp
new file mode 100644
index 0000000..d016692
--- /dev/null
+++ b/KJE/Tree.cpp
@@ -0,0 +1,37 @@
+//트리 구조 구현
+//전위순회: root->left->right
+#include <iostream>
+using namespace std;
+
+typedef struct Node{
+    int data;
+    struct Node*left;
+    struct Node*right;
+}Node;
+
+//루트 왼쪽 오른쪽 순
+struct Node n1={1, NULL,NULL};
+struct Node n2={4, &n1, NULL};
+struct Node n3={16, NULL, NULL};
+struct Node n4={25, NULL, NULL};
+struct Node n5={20, &n3, &n4};
+struct Node n6={15, &n2, &n5};
+struct Node *current=&n6;    //current가 루트
+//계속 오류가 났던 이유,,
+//Struct Node에서 int data를 맨 마지막에 썼는데 맨 위에 썼어야 했다. 순서 주의
+
+void Preorder(Node*current){
+    if(current){
+        cout<<current->data<<endl;
+        Preorder(current->left);
+        Preorder(current->right);
+    }
+}
+
+int main(){
+
+    cout<<"전위순회"<<endl;
+    Preorder(current);
+    return 0;
+    //출력: 15-4-1-20-16-25
+}
\ No newline at end of file