437 added

Author: aQua

Algorithms/0437.path-sum-iii/README.md

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+# [437. Path Sum III](https://leetcode.com/problems/path-sum-iii/)
+
+## 题目
+You are given a binary tree in which each node contains an integer value.
+
+Find the number of paths that sum to a given value.
+
+The path does not need to start or end at the root or a leaf, but it must go downwards
+(traveling only from parent nodes to child nodes).
+
+The tree has no more than 1,000 nodes and the values are in the range -1,000,000 to 1,000,000.
+
+Example:
+root = [10,5,-3,3,2,null,11,3,-2,null,1], sum = 8
+```
+      10
+     /  \
+    5   -3
+   / \    \
+  3   2   11
+ / \   \
+3  -2   1
+```
+Return 3. The paths that sum to 8 are:
+1.  5 -> 3
+2.  5 -> 2 -> 1
+3. -3 -> 11
+
+## 解题思路
+
+见程序注释

Algorithms/0437.path-sum-iii/path-sum-iii.go

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+package Problem0437
+
+import (
+	"github.com/aQuaYi/LeetCode-in-Golang/kit"
+)
+type TreeNode = kit.TreeNode
+
+func pathSum(root *TreeNode, sum int) int {
+res :=0
+
+	return res 
+}

Algorithms/0437.path-sum-iii/path-sum-iii_test.go

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+package Problem0437
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/aQuaYi/LeetCode-in-Golang/kit"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_Problem0437(t *testing.T) {
+	ast := assert.New(t)
+
+	// tcs is testcase slice
+	tcs := []struct {
+		pre, in []int
+		sum     int
+		ans     int
+	}{
+
+		{
+			[]int{10, 5, 3, 3, -2, 2, 1, -3, 11},
+			[]int{3, 3, -2, 5, 2, 1, 10, -3, 11},
+			8,
+			3,
+		},
+
+		// 可以多个 testcase
+	}
+
+	for _, tc := range tcs {
+		fmt.Printf("~~%v~~\n", tc)
+
+		ast.Equal(tc.ans, pathSum(kit.PreIn2Tree(tc.pre, tc.in), tc.sum), "输入:%v", tc)
+	}
+}