Sum root to leaf numbers

Signed-off-by: Leo Ma <begeekmyfriend@gmail.com>

Author: begeekmyfriend

129_sum_root_to_leaf_numbers/Makefile

@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test sum_tree.c

129_sum_root_to_leaf_numbers/sum_tree.c

@@ -0,0 +1,64 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+struct TreeNode {
+    int val;
+    struct TreeNode *left;
+    struct TreeNode *right;
+};
+
+static void recursive(struct TreeNode* node, int sum, int *total)
+{
+    sum = sum * 10 + node->val;
+
+    if (node->left == NULL && node->right == NULL) {
+        *total += sum;
+    }
+
+    if (node->left != NULL) {
+        recursive(node->left, sum, total);
+    }
+
+    if (node->right != NULL) {
+        recursive(node->right, sum, total);
+    }
+}
+
+static int sumNumbers(struct TreeNode* root)
+{
+    if (root == NULL) {
+        return 0;
+    }
+
+    int total = 0;
+    recursive(root, 0, &total);
+    return total;
+}
+
+int main(void)
+{
+    struct TreeNode root, n10, n11, n20, n21, n22, n23;
+    root.val = 1;
+    n10.val = 2;
+    n11.val = 2;
+    n20.val = 3;
+    n21.val = 4;
+    n22.val = 4;
+    n23.val = 3;
+    root.left = &n10;
+    root.right = &n11;
+    n10.left = &n20;
+    n10.right = &n21;
+    n11.left = &n22;
+    n11.right = &n23;
+    n20.left = NULL;
+    n20.right = NULL;
+    n21.left = NULL;
+    n21.right = NULL;
+    n22.left = NULL;
+    n22.right = NULL;
+    n23.left = NULL;
+    n23.right = NULL;
+    printf("%d\n", sumNumbers(&root));
+    return 0;
+}