872 solved. (#64)

Author: zwfang

README.md

@@ -110,6 +110,7 @@ continually updating 😃.
 * [257. Binary Tree Paths](src/0257_binary_tree_paths/binary_tree_paths.go)   *`binary tree`*
 * [404. Sum of Left Leaves](src/0404_sum_of_left_leaves/sum_of_left_leaves.go)   *`binary tree`*
 * [437. Path Sum III](src/0437_path_sum_3/path_sum_3.go)   *`binary tree`*
+* [872. Leaf-Similar Trees](src/0872_leaf_similar_trees/leaf_similar_trees.go)   *`binary tree`*
 
 ### Binary Search
 * [33. Search in Rotated Sorted Array](./src/0033_search_in_rotated_sorted_array/search_in_rotated_sorted_array.go)   *`array;`*  *`binary search`*

src/0872_leaf_similar_trees/leaf_similar_trees.go

@@ -0,0 +1,42 @@
+/*
+872. Leaf-Similar Trees
+https://leetcode.com/problems/leaf-similar-trees/
+*/
+// time: 2019-01-08
+
+package lst
+
+import (
+	"reflect"
+)
+
+// TreeNode Definition for a binary tree node.
+type TreeNode struct {
+	Val   int
+	Left  *TreeNode
+	Right *TreeNode
+}
+
+// time complexity: O(n1 + n2), where n is nodes number in the tree.
+// space complexity: O(h1 + h2), where h is height of the tree.
+func leafSimilar(root1 *TreeNode, root2 *TreeNode) bool {
+	l1 := make([]int, 0)
+	l2 := make([]int, 0)
+
+	dfs(root1, &l1)
+	dfs(root2, &l2)
+
+	return reflect.DeepEqual(l1, l2)
+}
+
+func dfs(root *TreeNode, l *[]int) {
+	if nil == root {
+		return
+	}
+
+	if root.Left == nil && root.Right == nil {
+		*l = append(*l, root.Val)
+	}
+	dfs(root.Left, l)
+	dfs(root.Right, l)
+}

src/0872_leaf_similar_trees/leaf_similar_trees_test.go

@@ -0,0 +1,40 @@
+package lst
+
+import (
+	"reflect"
+	"testing"
+)
+
+func createBinaryTree(nums []int) *TreeNode {
+	return performCreate(nums, 0)
+}
+
+func performCreate(nums []int, index int) *TreeNode {
+	if index >= len(nums) {
+		return nil
+	}
+
+	tree := TreeNode{Val: nums[index]}
+	tree.Left = performCreate(nums, 2*index+1)
+	tree.Right = performCreate(nums, 2*index+2)
+	return &tree
+}
+
+func TestLeafSimilar(t *testing.T) {
+	type arg struct {
+		root1, root2 *TreeNode
+	}
+
+	testCases := []arg{
+		{root1: createBinaryTree([]int{3, 5, 1, 6, 2, 9, 8}), root2: createBinaryTree([]int{6, 4, 1, 6, 2, 9, 8})},
+		{root1: createBinaryTree([]int{3, 5, 1, 6, 2, 9, 4}), root2: createBinaryTree([]int{6, 4, 1, 6, 2, 9, 8})},
+	}
+
+	expected := []bool{true, false}
+
+	for index, data := range testCases {
+		if res := leafSimilar(data.root1, data.root2); !reflect.DeepEqual(res, expected[index]) {
+			t.Errorf("expected %t, got %t", expected[index], res)
+		}
+	}
+}

src/README.md

@@ -101,3 +101,4 @@
 |0717|[717. 1-bit and 2-bit Characters](0717_1_bit_and_2_bit_characters/1bitand2bitc.go)|Easy||
 |0728|[Self Dividing Numbers](./0728_self_dividing_numbers/self_dividing_numbers.go)|Easy||
 |0747|[Largest Number At Least Twice of Others](./0747_largest_number_at_least_twice_of_others/largest_number_at_least_twice_of_others.go)|Easy||
+|0872|[872. Leaf-Similar Trees](0872_leaf_similar_trees/leaf_similar_trees.go)|Easy|*`binary tree`*|