#include <assert.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

struct TreeNode {

};

char* stringAdd(char* str, int val) {

char temp[10];

if(strlen(str) == 0)

sprintf(temp, "%d", val);

else

sprintf(temp, "->%d", val);

char *newStr = (char*)malloc(sizeof(char)*100);

strcpy(newStr, str);

strcat(newStr, temp);

return newStr;

}

void traverse(struct TreeNode *node, char* str, char** paths, int* returnSize) {

if(node->left!=NULL)

traverse(node->left, stringAdd(str, node->val), paths, returnSize);

if(node->right!=NULL)

traverse(node->right, stringAdd(str, node->val), paths, returnSize);

if(node->left==NULL && node->right==NULL) {

*(paths+*returnSize) = stringAdd(str, node->val);

(*returnSize)++;

}

}

/**

* Return an array of size *returnSize.

* Note: The returned array must be malloced, assume caller calls free().

*/

char** binaryTreePaths(struct TreeNode* root, int* returnSize) {

if(root == NULL)

return NULL;

char** paths = (char **)malloc(sizeof(char *)*100);

traverse(root, "", paths, returnSize);

return paths;

}

int main() {

struct TreeNode *root = (struct TreeNode *)malloc(sizeof(struct TreeNode *));

root->val = 1;

struct TreeNode *node1_1 = (struct TreeNode *)malloc(sizeof(struct TreeNode *));

node1_1->val = 2;

root->left = node1_1;

struct TreeNode *node1_2 = (struct TreeNode *)malloc(sizeof(struct TreeNode *));

node1_2->val = 3;

root->right = node1_2;

node1_2->left = NULL;

node1_2->right = NULL;

struct TreeNode *node2_1 = (struct TreeNode *)malloc(sizeof(struct TreeNode *));

node2_1->val = 5;

node1_1->left = NULL;

node1_1->right = node2_1;

node2_1->left = NULL;

node2_1->right = NULL;

int returnSize = 0;

char** paths = binaryTreePaths(root, &returnSize);

assert(returnSize == 2);

assert(strcmp(paths[0], "1->2->5") == 0);

assert(strcmp(paths[1], "1->3") == 0);

return 0;

}