@@ -19,9 +19,116 @@ public Node(int val) {
1919public class BinaryTree {
2020 Node root ;
2121
22+ /**
23+ * Pre-order - recursive
24+ * 1. Visit current node
25+ * 2. Visit left child
26+ * 3. Visit right child
27+ * */
28+ static void preOrder (Node root ) {
29+ if (null != root ) {
30+ System .out .printf ("%d " , root .val );
31+ preOrder (root .left );
32+ preOrder (root .right );
33+ }
34+ }
35+ 36+ /**
37+ * Post-order - recursive
38+ * 1. Visit left child
39+ * 2. Visit right child
40+ * 3. Visit current node
41+ * */
42+ static void postOrder (Node root ) {
43+ if (null != root ) {
44+ postOrder (root .left );
45+ postOrder (root .right );
46+ System .out .printf ("%d " , root .val );
47+ }
48+ }
49+ 50+ /**
51+ * In-order - recursive
52+ * 1. Visit left child
53+ * 2. Visit current node
54+ * 3. Visit right child
55+ * */
56+ static void inOrder (Node root ) {
57+ if (null != root ) {
58+ inOrder (root .left );
59+ System .out .printf ("%d " , root .val );
60+ inOrder (root .right );
61+ }
62+ }
2263
2364 /**
2465 * calculate height of binary tree - dfs
2566 * */
2667 static int heightOfTree () {return 0 ;}
68+ 69+ public static void main (String [] args ) {
70+ 71+ /**
72+ * 65
73+ * / \ ---level 1
74+ * / \
75+ * / \
76+ * 25 85 --- level 2
77+ * / \ / \
78+ * / \ / \
79+ * 15 35 75 95 -- level 3
80+ * / \ / \
81+ * / \ / \
82+ * 70 80 90 100 -- level 4
83+ *
84+ * PreOrder binary tree traversal :
85+ * 65 25 15 35 85 75 70 80 95 90 100
86+ *
87+ * PostOrder binary tree traversal :
88+ * 15 35 25 70 80 75 90 100 95 85 65
89+ *
90+ * InOrder binary tree traversal :
91+ * 15 25 35 65 70 75 80 85 90 95 100
92+ *
93+ * */
94+ 95+ // root level 0
96+ Node A = new Node (65 );
97+ // Level 1
98+ Node B = new Node (25 );
99+ Node C = new Node (85 );
100+ // Level 2
101+ Node D = new Node (15 );
102+ Node E = new Node (35 );
103+ Node F = new Node (75 );
104+ Node G = new Node (95 );
105+ // Level 3
106+ Node H = new Node (70 );
107+ Node I = new Node (80 );
108+ Node J = new Node (90 );
109+ Node K = new Node (100 );
110+ 111+ // connect Level 0 and 1
112+ A .left = B ;
113+ A .right = C ;
114+ // connect level 1 and level 2
115+ B .left = D ;
116+ B .right = E ;
117+ C .left = F ;
118+ C .right = G ;
119+ // connect level 2 and level 3
120+ F .left = H ;
121+ F .right = I ;
122+ G .left = J ;
123+ G .right = K ;
124+ 125+ System .out .println ("PreOrder binary tree traversal :" );
126+ preOrder (A );
127+ 128+ System .out .println ("\n PostOrder binary tree traversal :" );
129+ postOrder (A );
130+ 131+ System .out .println ("\n InOrder binary tree traversal : " );
132+ inOrder (A );
133+ }
27134}
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