June 1st problem done

problems/226/main.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+ // Definition for a binary tree node.
+struct TreeNode {
+    int val;
+    struct TreeNode *left;
+    struct TreeNode *right;
+};
+
+void printTree(struct TreeNode* tree) {
+    if (tree != NULL) {
+        printf(" %d ", tree->val);
+        printTree(tree->left);
+        printTree(tree->right);
+    }
+}
+
+
+struct TreeNode* invertTree(struct TreeNode* root){
+    if (root != NULL) {
+        struct TreeNode* temp = root->right;
+        root->right = root->left;
+        root->left = temp;
+        invertTree(root->left);
+        invertTree(root->right);
+    }
+    return root;
+}
+
+int main() {
+    struct TreeNode l = { 2, NULL, NULL };
+    struct TreeNode r = { 3, NULL, NULL };
+    struct TreeNode tree = { 1, &l, &r};
+    struct TreeNode* inverted = invertTree(&tree);
+    printf("Expected: 1  3  2 \n");
+    printf("Got:");
+    printTree(inverted);
+    printf("\n");
+    return 0;
+}

problems/226/problem.txt

@@ -0,0 +1,25 @@
+Invert a binary tree.
+
+Example:
+
+Input:
+
+     4
+   /   \
+  2     7
+ / \   / \
+1   3 6   9
+
+Output:
+
+     4
+   /   \
+  7     2
+ / \   / \
+9   6 3   1
+
+Trivia:
+This problem was inspired by this original tweet by Max Howell:
+
+    Google: 90% of our engineers use the software you wrote (Homebrew), but you can’t invert a binary tree on a whiteboard so f*** off.
+

problems/226/run.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+gcc -o main main.c
+./main
+rm main