From 2b24f02146b5f1834e91274206e88e5987647f83 Mon Sep 17 00:00:00 2001 From: cdx <614141165@qq.com> Date: Wed, 20 Dec 2017 17:16:28 +0800 Subject: [PATCH 1/7] my own leetcode view; --- src/me/codebase/leetcode/Test.java | 67 ++++++++++++++++++++++++++++++ src/me/codebase/leetcode/_002.java | 38 +++++++++++++++++ 2 files changed, 105 insertions(+) create mode 100644 src/me/codebase/leetcode/Test.java create mode 100644 src/me/codebase/leetcode/_002.java diff --git a/src/me/codebase/leetcode/Test.java b/src/me/codebase/leetcode/Test.java new file mode 100644 index 00000000..e7fe28bb --- /dev/null +++ b/src/me/codebase/leetcode/Test.java @@ -0,0 +1,67 @@ +package me.codebase.leetcode; + +import java.util.HashMap; +import java.util.Map; + +/** + * Created by chendong on 2017/12/13. + */ +public class Test { + + + public static void main(String[] args) { + Integer[] arr1 = {1, 2, 3}; + Integer[] arr2 = {2, 3, 4}; + + int mid1 = arr1.length / 2; + int mid2 = arr2.length / 2; + } + + /* public static int lengthOfLongestSubstring(String s) { + int len; + if (s == null || (len = s.length()) == 0) return 0; + int preP = 0, max = 0; + int[] hash = new int[128]; + for (int i = 0; i < len; ++i) { + char c = s.charAt(i); + if (hash[c] > preP) { + preP = hash[c]; + } + int l = i - preP + 1; + hash[c] = i + 1; + if (l > max) max = l; + } + return max; + } + */ + private static String distinct(String str) { + Map map = new HashMap<>(); + char[] chars = str.toCharArray(); + for (int i = 0; i < chars.length; i++) { + + if (map.get(chars[i]) != null) + map.put(chars[i], i - map.get(chars[i])); + else + map.put(chars[i], i); + } + return null; + } + + + + +/* + private static String findSubString(String str, int index) { + char[] chars = str.toCharArray(); + int l = 1; + for (int i = index; i < chars.length; i++) { + if (chars[i] != chars[i++]) { + l++; + }else break; + } + return String.valueOf() + } +*/ + + +} diff --git a/src/me/codebase/leetcode/_002.java b/src/me/codebase/leetcode/_002.java new file mode 100644 index 00000000..aa18dddd --- /dev/null +++ b/src/me/codebase/leetcode/_002.java @@ -0,0 +1,38 @@ +package me.codebase.leetcode; + +/** + * Created by chendong on 2017/12/13. + */ +public class _002 { + + private static Node add(Node n1, Node n2) { + int over = 0; + Node root = null; + Node node = null; + while (n1 != null && n2 != null) { + Node n = new Node(0); + n.val = (n1.val + n2.val + over) % 10; + over = (n1.val + n2.val) / 10; + n1 = n1.next; + n2 = n2.next; + if (node == null) { + node = n; + root = node; + } else + node.next = n; + if (node.next != null) + node = node.next; + } + return root; + } + + static class Node { + int val; + Node next; + + public Node(int val) { + this.val = val; + } + } + +} From 694d25cb9f535cfe0785a56a5c5304d710786005 Mon Sep 17 00:00:00 2001 From: cdx <614141165@qq.com> Date: Tue, 2 Jan 2018 13:52:26 +0800 Subject: [PATCH 2/7] 004 md --- note/004/README.md | 1 - src/me/codebase/leetcode/Test.java | 82 +++++++++++++----------------- src/me/codebase/leetcode/_004.java | 22 ++++++++ 3 files changed, 58 insertions(+), 47 deletions(-) create mode 100644 src/me/codebase/leetcode/_004.java diff --git a/note/004/README.md b/note/004/README.md index 521fc440..a711e193 100644 --- a/note/004/README.md +++ b/note/004/README.md @@ -47,7 +47,6 @@ The median is (2 + 3)/2 = 2.5 特别地，我们选取 `m = k / 2`，下面是我画的草图，希望能帮助大家理解。 -![](https://raw.githubusercontent.com/Blankj/awesome-java-leetcode/master/note/004/my_draw.jpg) 借助上面的理论，你能写出相关代码了吗？ diff --git a/src/me/codebase/leetcode/Test.java b/src/me/codebase/leetcode/Test.java index e7fe28bb..6861136f 100644 --- a/src/me/codebase/leetcode/Test.java +++ b/src/me/codebase/leetcode/Test.java @@ -1,8 +1,5 @@ package me.codebase.leetcode; -import java.util.HashMap; -import java.util.Map; - /** * Created by chendong on 2017/12/13. */ @@ -10,58 +7,51 @@ public class Test { public static void main(String[] args) { - Integer[] arr1 = {1, 2, 3}; - Integer[] arr2 = {2, 3, 4}; - - int mid1 = arr1.length / 2; - int mid2 = arr2.length / 2; - } + int[] A = {1, 3, 4, 6}; + int[] B = {2, 4, 5, 8, 9, 10}; + int[] C = {1, 2, 3, 4, 4, 5, 6, 8, 9, 10}; + // 4.5 - /* public static int lengthOfLongestSubstring(String s) { - int len; - if (s == null || (len = s.length()) == 0) return 0; - int preP = 0, max = 0; - int[] hash = new int[128]; - for (int i = 0; i < len; ++i) { - char c = s.charAt(i); - if (hash[c] > preP) { - preP = hash[c]; - } - int l = i - preP + 1; - hash[c] = i + 1; - if (l > max) max = l; - } - return max; - } - */ - private static String distinct(String str) { - Map map = new HashMap<>(); - char[] chars = str.toCharArray(); - for (int i = 0; i < chars.length; i++) { - if (map.get(chars[i]) != null) - map.put(chars[i], i - map.get(chars[i])); - else - map.put(chars[i], i); - } - return null; + System.out.println(findMedianSortedArrays(A, B)); } + /** + * satisfy the require which is should be O(log(m+n)) + *

+ * Array, Binary Search, Divide and Conquer + */ + private static int findKth(int k, int[] A, int[] B) { + return 0; + } -/* - private static String findSubString(String str, int index) { - char[] chars = str.toCharArray(); - int l = 1; - for (int i = index; i < chars.length; i++) { - if (chars[i] != chars[i++]) { - l++; - }else break; + private static int findKth(int k, int[] arr) { + return 0; + } + + public static double findMedianSortedArrays(int[] nums1, int[] nums2) { + int len = nums1.length + nums2.length; + if (len % 2 == 0) { + return (helper(nums1, 0, nums2, 0, len / 2) + helper(nums1, 0, nums2, 0, len / 2 + 1)) / 2.0; } - return String.valueOf() + return helper(nums1, 0, nums2, 0, (len + 1) / 2); } -*/ + private static int helper(int[] nums1, int m, int[] nums2, int n, int k) { + if (m >= nums1.length) return nums2[n + k - 1]; + if (n >= nums2.length) return nums1[m + k - 1]; + if (k == 1) return Math.min(nums1[m], nums2[n]); + + int p1 = m + k / 2 - 1; + int p2 = n + k / 2 - 1; + int mid1 = p1 < nums1.length ? nums1[p1] : Integer.MAX_VALUE; + int mid2 = p2 < nums2.length ? nums2[p2] : Integer.MAX_VALUE; + if (mid1 < mid2) { + return helper(nums1, m + k / 2, nums2, n, k - k / 2); + } + return helper(nums1, m, nums2, n + k / 2, k - k / 2); + } } diff --git a/src/me/codebase/leetcode/_004.java b/src/me/codebase/leetcode/_004.java new file mode 100644 index 00000000..88c59f66 --- /dev/null +++ b/src/me/codebase/leetcode/_004.java @@ -0,0 +1,22 @@ +package me.codebase.leetcode; + +import java.util.Arrays; + +/** + * Created by chendong on 2018/1/2. + */ +public class _004 { + + + public static void main(String[] args) { + int[] A = {1, 3, 4, 6}; + int[] B = {2, 4, 5, 8, 9, 10}; + int[] C = {1, 2, 3, 4, 4, 5, 6, 8, 9, 10}; + // 4.5 + System.out.println(Arrays.toString(args)); + +// System.out.println(findMedianSortedArrays(A, B)); + } + + +} From 8f7af9a9b1f9551d0d94c981594c0f32564235d4 Mon Sep 17 00:00:00 2001 From: cdx <614141165@qq.com> Date: Tue, 2 Jan 2018 17:27:16 +0800 Subject: [PATCH 3/7] :bug: this is a test; --- src/me/codebase/leetcode/_004.java | 1 - 1 file changed, 1 deletion(-) diff --git a/src/me/codebase/leetcode/_004.java b/src/me/codebase/leetcode/_004.java index 88c59f66..7d5f4f34 100644 --- a/src/me/codebase/leetcode/_004.java +++ b/src/me/codebase/leetcode/_004.java @@ -13,7 +13,6 @@ public static void main(String[] args) { int[] B = {2, 4, 5, 8, 9, 10}; int[] C = {1, 2, 3, 4, 4, 5, 6, 8, 9, 10}; // 4.5 - System.out.println(Arrays.toString(args)); // System.out.println(findMedianSortedArrays(A, B)); } From 3fc1e95cfc393ca994c3f53d77f5cf670e414f83 Mon Sep 17 00:00:00 2001 From: cdx <614141165@qq.com> Date: Sat, 6 Jan 2018 16:08:45 +0800 Subject: [PATCH 4/7] fix --- src/me/codebase/leetcode/_004.java | 38 +++++++++++++++++++++-- src/me/codebase/leetcode/_554.java | 49 ++++++++++++++++++++++++++++++ 2 files changed, 85 insertions(+), 2 deletions(-) create mode 100644 src/me/codebase/leetcode/_554.java diff --git a/src/me/codebase/leetcode/_004.java b/src/me/codebase/leetcode/_004.java index 7d5f4f34..b7515e30 100644 --- a/src/me/codebase/leetcode/_004.java +++ b/src/me/codebase/leetcode/_004.java @@ -1,7 +1,5 @@ package me.codebase.leetcode; -import java.util.Arrays; - /** * Created by chendong on 2018/1/2. */ @@ -14,8 +12,44 @@ public static void main(String[] args) { int[] C = {1, 2, 3, 4, 4, 5, 6, 8, 9, 10}; // 4.5 + Solution solution = new Solution(); + double median = solution.findMedianSortedArrays(A, B); + System.out.println(median); // System.out.println(findMedianSortedArrays(A, B)); } + private static double findMedian(int[] A, int[] B){ + + + + return 0; + } + + + static class Solution { + public double findMedianSortedArrays(int[] nums1, int[] nums2) { + int len = nums1.length + nums2.length; + if (len % 2 == 0) { + return (helper(nums1, 0, nums2, 0, len / 2) + helper(nums1, 0, nums2, 0, len / 2 + 1)) / 2.0; + } + return helper(nums1, 0, nums2, 0, (len + 1) / 2); + } + + private int helper(int[] nums1, int m, int[] nums2, int n, int k) { + if (m >= nums1.length) return nums2[n + k - 1]; + if (n >= nums2.length) return nums1[m + k - 1]; + if (k == 1) return Math.min(nums1[m], nums2[n]); + + int p1 = m + k / 2 - 1; + int p2 = n + k / 2 - 1; + int mid1 = p1 < nums1.length ? nums1[p1] : Integer.MAX_VALUE; + int mid2 = p2 < nums2.length ? nums2[p2] : Integer.MAX_VALUE; + if (mid1 < mid2) { + return helper(nums1, m + k / 2, nums2, n, k - k / 2); + } + return helper(nums1, m, nums2, n + k / 2, k - k / 2); + } + } + } diff --git a/src/me/codebase/leetcode/_554.java b/src/me/codebase/leetcode/_554.java new file mode 100644 index 00000000..8d336951 --- /dev/null +++ b/src/me/codebase/leetcode/_554.java @@ -0,0 +1,49 @@ +package me.codebase.leetcode; + +import java.util.ArrayList; +import java.util.List; + +/** + * Created by chendong on 2018/1/5. + */ +public class _554 { + + /* + input: + [[1,2,2,1], + [3,1,2], + [1,3,2], + [2,4], + [3,1,2], + [1,3,1,1]] + output: + 2 + */ + + public static void main(String[] args) { + List input = new ArrayList<>(); + input.add(new Integer[]{1, 2, 2, 1}); + input.add(new Integer[]{3, 1, 2}); + input.add(new Integer[]{1, 3, 2}); + input.add(new Integer[]{2, 4}); + input.add(new Integer[]{3, 1, 2}); + input.add(new Integer[]{1, 3, 1, 1}); + solution(input); + } + + private static int solution(List input) { + int result = 0; + List points = new ArrayList<>(input.size()); + for (Integer[] breaks : input) { + List list = new ArrayList<>(); + int point = 0; + for (Integer integer : breaks) { + point += integer; + list.add(point); + } + points.add(list.toArray(new Integer[list.size()])); + } + + return result; + } +} From 7a984396ded3e1fbcc13a59be51d857495569d8b Mon Sep 17 00:00:00 2001 From: cdx <614141165@qq.com> Date: Wed, 10 Jan 2018 16:43:42 +0800 Subject: [PATCH 5/7] :bento: Adding or updating assets. _554; --- src/me/codebase/leetcode/Test.java | 46 ------------------- src/me/codebase/leetcode/_543.java | 11 +++++ src/me/codebase/leetcode/_554.java | 20 ++++++-- .../codebase/leetcode/structure/TreeNode.java | 14 ++++++ 4 files changed, 40 insertions(+), 51 deletions(-) create mode 100644 src/me/codebase/leetcode/_543.java create mode 100644 src/me/codebase/leetcode/structure/TreeNode.java diff --git a/src/me/codebase/leetcode/Test.java b/src/me/codebase/leetcode/Test.java index 6861136f..37f8a326 100644 --- a/src/me/codebase/leetcode/Test.java +++ b/src/me/codebase/leetcode/Test.java @@ -5,53 +5,7 @@ */ public class Test { - public static void main(String[] args) { - int[] A = {1, 3, 4, 6}; - int[] B = {2, 4, 5, 8, 9, 10}; - int[] C = {1, 2, 3, 4, 4, 5, 6, 8, 9, 10}; - // 4.5 - - - System.out.println(findMedianSortedArrays(A, B)); - } - - - /** - * satisfy the require which is should be O(log(m+n)) - *

- * Array, Binary Search, Divide and Conquer - */ - private static int findKth(int k, int[] A, int[] B) { - - return 0; - } - - private static int findKth(int k, int[] arr) { - return 0; - } - public static double findMedianSortedArrays(int[] nums1, int[] nums2) { - int len = nums1.length + nums2.length; - if (len % 2 == 0) { - return (helper(nums1, 0, nums2, 0, len / 2) + helper(nums1, 0, nums2, 0, len / 2 + 1)) / 2.0; - } - return helper(nums1, 0, nums2, 0, (len + 1) / 2); } - - private static int helper(int[] nums1, int m, int[] nums2, int n, int k) { - if (m >= nums1.length) return nums2[n + k - 1]; - if (n >= nums2.length) return nums1[m + k - 1]; - if (k == 1) return Math.min(nums1[m], nums2[n]); - - int p1 = m + k / 2 - 1; - int p2 = n + k / 2 - 1; - int mid1 = p1 < nums1.length ? nums1[p1] : Integer.MAX_VALUE; - int mid2 = p2 < nums2.length ? nums2[p2] : Integer.MAX_VALUE; - if (mid1 < mid2) { - return helper(nums1, m + k / 2, nums2, n, k - k / 2); - } - return helper(nums1, m, nums2, n + k / 2, k - k / 2); - } - } diff --git a/src/me/codebase/leetcode/_543.java b/src/me/codebase/leetcode/_543.java new file mode 100644 index 00000000..15192a4d --- /dev/null +++ b/src/me/codebase/leetcode/_543.java @@ -0,0 +1,11 @@ +package me.codebase.leetcode; + +/** + * Created by chendong on 2018/1/10. + */ +public class _543 { + + public static void main(String[] args) { + + } +} diff --git a/src/me/codebase/leetcode/_554.java b/src/me/codebase/leetcode/_554.java index 8d336951..65e42bed 100644 --- a/src/me/codebase/leetcode/_554.java +++ b/src/me/codebase/leetcode/_554.java @@ -28,12 +28,12 @@ public static void main(String[] args) { input.add(new Integer[]{2, 4}); input.add(new Integer[]{3, 1, 2}); input.add(new Integer[]{1, 3, 1, 1}); - solution(input); + System.out.println(solution(input)); } private static int solution(List input) { - int result = 0; - List points = new ArrayList<>(input.size()); + int result = -1; + List> points = new ArrayList<>(input.size()); for (Integer[] breaks : input) { List list = new ArrayList<>(); int point = 0; @@ -41,9 +41,19 @@ private static int solution(List input) { point += integer; list.add(point); } - points.add(list.toArray(new Integer[list.size()])); + points.add(list); + } + List last = points.get(points.size() - 1); + for (int i = 0; i < last.size() - 1; i++) { + int temp = 0; + for (List breaks : points) { + if (!breaks.contains(last.get(i))) + temp++; + } + if (result == -1) + result = temp; + result = temp > result ? result : temp; } - return result; } } diff --git a/src/me/codebase/leetcode/structure/TreeNode.java b/src/me/codebase/leetcode/structure/TreeNode.java new file mode 100644 index 00000000..eff4dd5f --- /dev/null +++ b/src/me/codebase/leetcode/structure/TreeNode.java @@ -0,0 +1,14 @@ +package me.codebase.leetcode.structure; + +/** + * Created by chendong on 2018/1/10. + */ +public class TreeNode { + int val; + TreeNode left; + TreeNode right; + + TreeNode(int x) { + val = x; + } +} From 790d8994381b15301c0d8187d58f24a22f9c2a43 Mon Sep 17 00:00:00 2001 From: cdx <614141165@qq.com> Date: Fri, 12 Jan 2018 09:47:50 +0800 Subject: [PATCH 6/7] :bento: Adding or updating assets. add QuickSort Exc --- src/me/codebase/leetcode/_543.java | 9 ++++ src/me/codebase/leetcode/algo/QuickSort.java | 48 +++++++++++++++++++ .../codebase/leetcode/structure/TreeNode.java | 6 +-- 3 files changed, 60 insertions(+), 3 deletions(-) create mode 100644 src/me/codebase/leetcode/algo/QuickSort.java diff --git a/src/me/codebase/leetcode/_543.java b/src/me/codebase/leetcode/_543.java index 15192a4d..8857dc0d 100644 --- a/src/me/codebase/leetcode/_543.java +++ b/src/me/codebase/leetcode/_543.java @@ -1,5 +1,7 @@ package me.codebase.leetcode; +import me.codebase.leetcode.structure.TreeNode; + /** * Created by chendong on 2018/1/10. */ @@ -8,4 +10,11 @@ public class _543 { public static void main(String[] args) { } + + + private static TreeNode getTree(){ + + return new TreeNode(1); + + } } diff --git a/src/me/codebase/leetcode/algo/QuickSort.java b/src/me/codebase/leetcode/algo/QuickSort.java new file mode 100644 index 00000000..6352bd52 --- /dev/null +++ b/src/me/codebase/leetcode/algo/QuickSort.java @@ -0,0 +1,48 @@ +package me.codebase.leetcode.algo; + +import java.util.Arrays; + +/** + * Created by chendong on 2018/1/11. + */ +public class QuickSort { + + private static final int[] arr = {0, 2, 4, 6, 8, 5, 3, 7, 9, 1, 400}; + + public static void main(String[] args) { + System.out.println(Arrays.toString(new QuickSort().sort(arr))); + } + + public int[] sort(int[] arr) { + sort(0, arr.length - 1, arr); + return arr; + } + + public void sort(int left, int right, int[] arr) { + if (right > left) { + int mid = partition(left, right, arr); + sort(left, mid - 1, arr); + sort(mid + 1, right, arr); + } + } + + private int partition(int left, int right, int[] arr) { + int mid = (left + right) / 2; + swap(mid, right, arr); + int index = left; + for (int i = left; i < right; i++) { + if (arr[i] < arr[right]) { + swap(i, index, arr); + index++; + } + } + swap(index, right, arr); + return index; + } + + private void swap(int i, int j, int[] arr) { + int temp = arr[i]; + arr[i] = arr[j]; + arr[j] = temp; + } +} diff --git a/src/me/codebase/leetcode/structure/TreeNode.java b/src/me/codebase/leetcode/structure/TreeNode.java index eff4dd5f..99a84f18 100644 --- a/src/me/codebase/leetcode/structure/TreeNode.java +++ b/src/me/codebase/leetcode/structure/TreeNode.java @@ -5,10 +5,10 @@ */ public class TreeNode { int val; - TreeNode left; - TreeNode right; + public TreeNode left; + public TreeNode right; - TreeNode(int x) { + public TreeNode(int x) { val = x; } } From 39ff61b477876be9fb7d20b1dc77eb5b7035e4f9 Mon Sep 17 00:00:00 2001 From: cdx <614141165@qq.com> Date: Wed, 17 Jan 2018 14:14:40 +0800 Subject: [PATCH 7/7] :bento: exercise; --- src/me/codebase/leetcode/algo/MergeSort.java | 54 +++++++++++++++++++ src/me/codebase/leetcode/algo/QuickSort.java | 3 +- src/me/codebase/leetcode/algo/Sort.java | 10 ++++ .../codebase/leetcode/algo/TreeBuilder.java | 13 +++++ 4 files changed, 78 insertions(+), 2 deletions(-) create mode 100644 src/me/codebase/leetcode/algo/MergeSort.java create mode 100644 src/me/codebase/leetcode/algo/Sort.java create mode 100644 src/me/codebase/leetcode/algo/TreeBuilder.java diff --git a/src/me/codebase/leetcode/algo/MergeSort.java b/src/me/codebase/leetcode/algo/MergeSort.java new file mode 100644 index 00000000..7f9da962 --- /dev/null +++ b/src/me/codebase/leetcode/algo/MergeSort.java @@ -0,0 +1,54 @@ +package me.codebase.leetcode.algo; + +import java.util.Arrays; + +/** + * Created by chendong on 2018/1/12. + */ +public class MergeSort implements Sort { + + + public static void main(String[] args) { +// sort(arr); + System.out.println(Arrays.toString(new MergeSort().sort(arr))); + } + +/* public int[] sort(int[] a){ + int[] h = a.clone(); + return a; + }*/ + + + + public int[] sort(int[] a) { + int[] helper = a.clone(); + sort(a, 0, a.length - 1, helper); + return arr; + } + + private static void sort(int[] a, int lo, int hi, int[] helper) { + if (lo >= hi) return; + int mid = (lo + hi) / 2; + sort(a, lo, mid, helper); + sort(a, mid + 1, hi, helper); + merge(a, lo, mid, hi, helper); + } + + private static void merge(int[] a, int lo, int mid, int hi, int[] helper) { + + System.arraycopy(a, lo, helper, lo, hi + 1 - lo); + int i = lo; + int j = mid + 1; + for (int k = lo; k <= hi; k++) { + if (i > mid) + a[k] = helper[j++]; + else if (j > hi) + a[k] = helper[i++]; + else if (helper[i] <= helper[j]) + a[k] = helper[i++]; + else + a[k] = helper[j++]; + } + + } +} diff --git a/src/me/codebase/leetcode/algo/QuickSort.java b/src/me/codebase/leetcode/algo/QuickSort.java index 6352bd52..a7c24450 100644 --- a/src/me/codebase/leetcode/algo/QuickSort.java +++ b/src/me/codebase/leetcode/algo/QuickSort.java @@ -5,9 +5,8 @@ /** * Created by chendong on 2018/1/11. */ -public class QuickSort { +public class QuickSort implements Sort{ - private static final int[] arr = {0, 2, 4, 6, 8, 5, 3, 7, 9, 1, 400}; public static void main(String[] args) { System.out.println(Arrays.toString(new QuickSort().sort(arr))); diff --git a/src/me/codebase/leetcode/algo/Sort.java b/src/me/codebase/leetcode/algo/Sort.java new file mode 100644 index 00000000..e4419fce --- /dev/null +++ b/src/me/codebase/leetcode/algo/Sort.java @@ -0,0 +1,10 @@ +package me.codebase.leetcode.algo; + +/** + * Created by chendong on 2018/1/12. + */ +public interface Sort { + + int[] arr = {0, 2, 4, 6, 8, 5, 3, 7, 9, 1, 400}; + +} diff --git a/src/me/codebase/leetcode/algo/TreeBuilder.java b/src/me/codebase/leetcode/algo/TreeBuilder.java new file mode 100644 index 00000000..cafbed30 --- /dev/null +++ b/src/me/codebase/leetcode/algo/TreeBuilder.java @@ -0,0 +1,13 @@ +package me.codebase.leetcode.algo; + +import me.codebase.leetcode.structure.TreeNode; + +/** + * Created by chendong on 2018/1/12. + */ +public class TreeBuilder { + + public static TreeNode getRootNode(){ + return null; + } +}