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import java.util.LinkedList;
import java.util.Queue;
public class InorderPostOrderToTree {
public static int pIndex = 0;
public Node makeBTree(int[] inOrder, int[] postOrder, int iStart, int iEnd,
int postStart, int postEnd) {
if (iStart > iEnd || postEnd > postEnd) {
return null;
}
int rootValue = postOrder[postEnd];
Node root = new Node(rootValue);
pIndex++;
if (iStart == iEnd) {
return root;
}
int index = getInorderIndex(inOrder, iStart, iEnd, root.data);
root.left = makeBTree(inOrder, postOrder, iStart, index - 1, postStart,
postStart + index - (iStart + 1));
root.right = makeBTree(inOrder, postOrder, index + 1, iEnd, postStart
+ index - iStart, postEnd - 1);
// }
return root;
}
public int getInorderIndex(int[] inOrder, int start, int end, int data) {
for (int i = start; i <= end; i++) {
if (inOrder[i] == data) {
return i;
}
}
return -1;
}
public void printINORDER(Node root) {
if (root != null) {
printINORDER(root.left);
System.out.print(" " + root.data);
printINORDER(root.right);
}
}
public static void main(String[] args) throws java.lang.Exception {
int[] inOrder = { 4, 2, 5, 1, 6, 3, 7 };
int[] postOrder = { 4, 5, 2, 6, 7, 3, 1 };
InorderPostOrderToTree i = new InorderPostOrderToTree();
Node x = i.makeBTree(inOrder, postOrder, 0, inOrder.length - 1, 0,
postOrder.length - 1);
System.out.println("inorder traversal of constructed tree : ");
i.printINORDER(x);
}
}
class Node {
int data;
Node left;
Node right;
public Node(int data) {
this.data = data;
left = null;
right = null;
}
}
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