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-rw-r--r--add_one_row_tree.c49
1 files changed, 49 insertions, 0 deletions
diff --git a/add_one_row_tree.c b/add_one_row_tree.c
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--- /dev/null
+++ b/add_one_row_tree.c
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+// 623. Add One Row to Tree
+#include "leetcode.h"
+
+/*
+ * given the 'root' of a binary tree and two integers 'val' and 'depth', add a
+ * row of nodes with value 'val' at the given depth 'depth'. note that 'root'
+ * node is at depth 1. the adding rule is given the integer 'depth' for each
+ * non-null tree node 'curr' at the depth 'depth - 1' create two tree nodes with
+ * value 'val' as 'curr's left subtree root and right subtree root. 'curr's
+ * original left subtree should be the left subtree of the new left subtree
+ * root. if 'depth == 1' that means that there is no depth 'depth - 1' at all,
+ * then create a tree node with value 'val' as the new root of the whole
+ * original tree, and the original tree is the new left subtree.
+ */
+
+struct TreeNode {
+ int val;
+ struct TreeNode *left;
+ struct TreeNode *right;
+};
+
+struct TreeNode *addOneRow(struct TreeNode *root, int val, int depth) {
+ if (depth == 1) {
+ struct TreeNode *new = malloc(sizeof(struct TreeNode));
+ new->val = val;
+ new->left = root;
+ new->right = NULL;
+ root = new;
+ return root;
+ }
+ if (depth == 2) {
+ struct TreeNode *left = malloc(sizeof(struct TreeNode));
+ struct TreeNode *right = malloc(sizeof(struct TreeNode));
+ left->val = val;
+ right->val = val;
+ left->left = root->left;
+ left->right = NULL;
+ right->right = root->right;
+ right->left = NULL;
+ root->left = left;
+ root->right = right;
+ return root;
+ }
+ if (root->left)
+ addOneRow(root->left, val, depth - 1);
+ if (root->right)
+ addOneRow(root->right, val, depth - 1);
+ return root;
+}