Software Engineer

Ninja is now bored with numbers and is now playing with characters but hates when he gets repeated characters. Ninja is provided a string, and he wants to return the first unique character in the string.The string will contain characters only from the English alphabet set, i.e., ('A' - 'Z') and ('a' - 'z'). If there is no non-repeating character, print the first character of the string. If there is no non-repeating character, return the first character of the string.

Bob went to his favourite bakery to buy some pastries. After picking up his favourite pastries his total bill was P cents. Bob lives in Berland where all the money is in the form of coins with denominations {1, 2, 5, 10, 20, 50, 100, 500, 1000}.

Bob is not very good at maths and thinks fewer coins mean less money and he will be happy if he gives minimum number of coins to the shopkeeper. Help Bob to find the minimum number of coins that sums to P cents (assume that Bob has an infinite number of coins of all denominations).

You are given the ‘ROOT’ of a binary tree with ‘N’ nodes where each node in the tree has some coins, and there are ‘N’ coins total. In one move, we may choose two adjacent nodes and move one coin from one node to another.

Your task is to return the number of moves required to make every node have exactly one coin.

Note:

A move may be from parent to child or from child to parent.

For example,

Given ‘ROOT’ = [2,-1,0,-1,-1]

The tree would look like this : 

The answer would be 1, because the root node will transfer 1 coin to its right child. Thus both nodes have the same number of coins now.

You are given some information about the rooms of a military camp. The rooms are numbered from 0 to 'N-1'. Each room contains keys to some other rooms. You can visit a room only if you have a key to that room. Your task is to determine whether each room can be visited or not.

Note:

1. Room 0 is the only room that is initially unlocked and doesn’t require any key to enter.

2. Any other room can be visited only if you have the key to that room.

3. More than one room can have keys to the same room.

4. You are allowed to visit rooms in any order.

5. You can visit any room multiple times.