124 added

Author: aQua

Algorithms/0124.binary-tree-maximum-path-sum/README.md

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+# [124. Binary Tree Maximum Path Sum](https://leetcode.com/problems/binary-tree-maximum-path-sum/)
+
+## 题目
+Given a binary tree, find the maximum path sum.
+
+For this problem, a path is defined as any sequence of nodes from some starting node to any node in the tree along the parent-child connections. The path must contain at least one node and does not need to go through the root.
+
+For example:
+```
+Given the below binary tree,
+       1
+      / \
+     2   3
+
+Return 6.
+```
+## 解题思路
+
+见程序注释

Algorithms/0124.binary-tree-maximum-path-sum/binary-tree-maximum-path-sum.go

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+package Problem0124
+
+import (
+	"github.com/aQuaYi/LeetCode-in-Golang/kit"
+)
+type TreeNode = kit.TreeNode
+
+func maxPathSum(root *TreeNode) int {
+
+	return 22
+}

Algorithms/0124.binary-tree-maximum-path-sum/binary-tree-maximum-path-sum_test.go

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+package Problem0124
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/aQuaYi/LeetCode-in-Golang/kit"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_Problem0124(t *testing.T) {
+	ast := assert.New(t)
+
+	// tcs is testcase slice
+	tcs := []struct {
+		pre, in []int
+		ans     int
+	}{
+
+		{
+			[]int{1, 2, 3},
+			[]int{2, 1, 3},
+			6,
+		},
+
+		{
+			[]int{4, 2, 1, 3, 6, 5, 7},
+			[]int{1, 2, 3, 4, 5, 6, 7},
+			22,
+		},
+
+		// 可以多个 testcase
+	}
+
+	for _, tc := range tcs {
+		fmt.Printf("~~%v~~\n", tc)
+
+		root := kit.PreIn2Tree(tc.pre, tc.in)
+		ast.Equal(tc.ans, maxPathSum(root), "输入:%v", tc)
+	}
+}