Populating Next Right Pointers in Each Node

Author: illuz

solutions/116.Populating_Next_Right_Pointers_in_Each_Node/AC_simulation_n.cpp

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+/*
+*  Author:      illuz <iilluzen[at]gmail.com>
+*  File:        AC_simulation_n.cpp
+*  Create Date: 2015-02-22 09:56:58
+*  Descripton:  Link children layer by layer, O(1) space
+*               The code can accept in II version.
+*/
+
+#include <bits/stdc++.h>
+
+using namespace std;
+const int N = 0;
+
+// Definition for binary tree with next pointer.
+struct TreeLinkNode {
+ int val;
+ TreeLinkNode *left, *right, *next;
+ TreeLinkNode(int x) : val(x), left(NULL), right(NULL), next(NULL) {}
+};
+
+class Solution {
+public:
+    void connect(TreeLinkNode *root) {
+		TreeLinkNode header(0);
+		header.next = root;
+		TreeLinkNode *cur, *prev;
+		while (header.next) {
+			// current header's link is already populated
+			// following will make a new children-link to header
+			cur = header.next;
+			prev = &header;
+			header.next = nullptr;
+			for (; cur; cur = cur->next) {
+				if (cur->left != nullptr) {
+					prev->next = cur->left;
+					prev = prev->next;
+				}
+				if (cur->right != nullptr) {
+					prev->next = cur->right;
+					prev = prev->next;
+				}
+			}
+		}
+    }
+};
+
+int main() {
+	TreeLinkNode root(1);
+	Solution s;
+	s.connect(&root);
+	return 0;
+}
+

solutions/116.Populating_Next_Right_Pointers_in_Each_Node/AC_simulation_n.java

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+/*
+*  Author:      illuz <iilluzen[at]gmail.com>
+*  File:        AC_simulation_n.java
+*  Create Date: 2015-02-22 10:45:21
+*  Descripton:   
+*/
+
+import java.util.Scanner;
+
+public class Solution {
+
+    // Definition for binary tree with next pointer.
+    public class TreeLinkNode {
+        int val;
+        TreeLinkNode left, right, next;
+        TreeLinkNode(int x) { val = x; }
+    }
+
+    public void connect(TreeLinkNode root) {
+        TreeLinkNode header = new TreeLinkNode(0);
+        header.next = root;
+        TreeLinkNode cur, prev;
+        while (header.next != null) {
+            // current header's link is already populated
+            // following will make a new children-link to header
+            cur = header.next;
+            prev = header;
+            header.next = null;
+            for (; cur != null; cur = cur.next) {
+                if (cur.left != null) {
+                    prev.next = cur.left;
+                    prev = prev.next;
+                }
+                if (cur.right != null) {
+                    prev.next = cur.right;
+                    prev = prev.next;
+                }
+            }
+        }
+    }
+
+    // debug
+    public static void main(String[] args) {
+        Scanner cin = new Scanner(System.in);
+        Solution s = new Solution();
+        int[] input = {1, 2, 3, 1};
+        System.out.println("no case");
+    }
+}

solutions/116.Populating_Next_Right_Pointers_in_Each_Node/AC_simulation_n.py

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+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+# Author:      illuz <iilluzen[at]gmail.com>
+# File:        AC_simulation_n.py
+# Create Date: 2015-02-22 10:32:38
+# Usage:       AC_simulation_n.py 
+# Descripton:  
+
+
+# Definition for a  binary tree node
+class TreeNode:
+    def __init__(self, x):
+        self.val = x
+        self.left = None
+        self.right = None
+        self.next = None
+
+class Solution:
+    # @param root, a tree node
+    # @return nothing
+    def connect(self, root):
+        header = TreeNode(0)
+        header.next = root
+        while header.next:
+            cur = header.next
+            prev = header
+            header.next = None
+            while cur:
+                if cur.left:
+                    prev.next = cur.left
+                    prev = prev.next
+                if cur.right:
+                    prev.next = cur.right
+                    prev = prev.next
+                cur = cur.next
+
+# debug
+root = TreeNode(0)
+s = Solution()
+s.connect(root)
+