SDE - 1

Ninja has enrolled in a system design course at Coding Ninjas, and his first assignment is to create a search autocomplete system for a search engine.

Ninja is given ‘N’ sentences ‘SENTENCES’ and ‘N’ integers ‘TIMES’, where ‘TIMES’[i] is the number of times the ‘SENTENCES’[i] was typed. Now, the instructor will input a test sentence(at least one word and end with ‘#’). As Ninja’s best friend, can you help him with the assignment?

Your task is to implement the AutocompleteSystemclass:

• AutocompleteSystem(String[] sentences, int[] times)Initializes the object with the sentences and times arrays.
• List input(char c)This indicates that the user typed the character c.
  • Returns an empty array [], if c == '#' and stores the inputted sentence in the system.
  • Returns the top 3 historical hot sentences with the same prefix as the sentence already typed. If there are fewer than 3matches, return them all.

Here are the specific rules:

• A sentence’s hot degree is defined as the number of times a user typed the same sentence before.
• The returned top 3 hot sentences should be sorted by hot degree (The first is the hottest one). If several sentences have the same hot degree, use ASCII-code order (smaller one appears first).
• If less than three hot sentences exist, return as many as possible.
• When the input is a special character, it means the sentence ends, and in this case, you need to return an empty list.

For Example:

Input:
["AutocompleteSystem","input","input","input"]
[[["i want to join faang","icecream","i love coding ninjas"],[4,3,1],["i"],["s"],["#"]]

Output:
[null,["i want to join faang","icecream","i love coding ninjas"],[],[]]

Explanation:
* AutocompleteSystem obj = new AutocompleteSystem(["i want to join faang","icecream","i love coding ninjas"],[4,3,1]); 
* obj.input(“i”); // return ["i want to join faang","icecream","i love coding ninjas"]. There are three sentences that have prefix "I".
* obj.input(“s”); // return []. There is no sentence with prefix “is”
* obj.input(“#”); // return [].

You are given a circular array 'a' of length 'n'.

A circular array is an array in which we consider the first element is next of the last element. That is, the next element of 'a[n - 1]' is 'a[0]'.

Find the Next Greater Element(NGE) for every element.

The Next Greater Element for an element 'x' is the first element on the right side of 'x' in the array, which is greater than 'x'.

If no greater elements exist to the right of 'x', consider the next greater element as -1.

Example:

Input: 'a' = [1, 5, 3, 4, 2]

Output: NGE = [5, -1, 4, 5, 5]

Explanation: For the given array,

- The next greater element for 1 is 5.

- There is no greater element for 5 on the right side. So we consider NGE as -1.

- The next greater element for 3 is 4.

- The next greater element for 4 is 5, when we consider the next elements as 4 -> 2 -> 1 -> 5.

- The next greater element for 2 is 5, when we consider the next elements as 2 -> 1 -> 5.

Aahad and Harshit always have fun by solving problems. Harshit took a sorted array consisting of distinct integers and rotated it clockwise by an unknown amount. For example, he took a sorted array = [1, 2, 3, 4, 5] and if he rotates it by 2, then the array becomes: [4, 5, 1, 2, 3].

After rotating a sorted array, Aahad needs to answer Q queries asked by Harshit, each of them is described by one integer Q[i]. which Harshit wanted him to search in the array. For each query, if he found it, he had to shout the index of the number, otherwise, he had to shout -1.

For each query, you have to complete the given method where 'key' denotes Q[i]. If the key exists in the array, return the index of the 'key', otherwise, return -1.

Note:

Can you solve each query in O(logN) ?

You're given a string 'S' consisting of "{", "}", "(", ")", "[" and "]" .

Return true if the given string 'S' is balanced, else return false.

For example:

'S' = "{}()".

There is always an opening brace before a closing brace i.e. '{' before '}', '(' before ').
So the 'S' is Balanced.

Introduce yourself briefly.

What do you mean by innovation?

What can you offer to us in terms of your past work?