find height of binary tree, Find first repeating character, Find number of Islands

Question

Accepted Answer

The candidate is asked to solve three common coding problems related to binary trees, strings, and matrices.

To find the height of a binary tree, you can use a recursive function to traverse the tree and calculate the height at each node.
To find the first repeating character in a string, you can use a hashmap to store the frequency of each character and then iterate through the string to find the first character with a frequency greater than 1.
To find the number of islands in a matrix, you can use a depth-first search (DFS) algorithm to traverse the matrix and mark connected '1's as visited to count the number of distinct islands.

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