Merge pull request bhrigukansra#126 from InnovativeCoder/master

Pair sum using Inorder BST done

Author: Bhrigu Kansra

.DS_Store

@@ -0,0 +1,82 @@
+   #include <stack>
+
+int countNodes(BinaryTreeNode<int> *root) {
+	if(root == NULL) {
+		return 0;
+	}
+	return countNodes(root -> left) + countNodes(root -> right) + 1;
+}
+
+void printNodesSumToS(BinaryTreeNode<int> *root, int s) {
+	if(root == NULL) {
+		return;
+	}
+	int totalCount = countNodes(root);
+	int count = 0;
+	stack<BinaryTreeNode<int>*> inorder;
+	stack<BinaryTreeNode<int>*> revInorder;
+	BinaryTreeNode<int> *temp = root;
+	while(temp != NULL) {
+		inorder.push(temp);
+		temp = temp -> left;
+	}
+	temp = root;
+	while(temp != NULL) {
+		revInorder.push(temp);
+		temp = temp -> right;
+	}
+
+	while(count < totalCount - 1) {
+		BinaryTreeNode<int> *top1 = inorder.top();
+		BinaryTreeNode<int> *top2 = revInorder.top();
+		if(top1 -> data + top2 -> data == s) {
+			cout << top1 -> data << " " << top2 -> data << endl;
+
+			BinaryTreeNode<int> *top = top1;
+			inorder.pop();
+			count++;
+			if(top -> right != NULL) {
+				top = top -> right;
+				while(top != NULL) {
+					inorder.push(top);
+					top = top -> left;
+				}
+			}
+
+			top = top2;
+			revInorder.pop();
+			count++;
+			if(top -> left != NULL) {
+				top = top -> left;
+				while(top != NULL) {
+					revInorder.push(top);
+					top = top -> right;
+				}
+			}
+		}
+		else if(top1 -> data + top2 -> data > s) {
+			BinaryTreeNode<int> *top = top2;
+			revInorder.pop();
+			count++;
+			if(top -> left != NULL) {
+				top = top -> left;
+				while(top != NULL) {
+					revInorder.push(top);
+					top = top -> right;
+				}
+			}
+		}
+		else {
+			BinaryTreeNode<int> *top = top1;
+			inorder.pop();
+			count++;
+			if(top -> right != NULL) {
+				top = top -> right;
+				while(top != NULL) {
+					inorder.push(top);
+					top = top -> left;
+				}
+			}
+		}
+	}
+}