SDE - Intern

Ninja has been given a string ‘STR’ containing either ‘{’ or ‘}’. 'STR’ is called valid if all the brackets are balanced. Formally for each opening bracket, there must be a closing bracket right to it.

For Example:

“{}{}”, “{{}}”, “{{}{}}” are valid strings while “}{}”, “{}}{{}”, “{{}}}{“ are not valid strings.

Ninja wants to make ‘STR’ valid by performing some operations on it. In one operation, he can convert ‘{’ into ‘}’ or vice versa, and the cost of one such operation is 1.

Your task is to help Ninja determine the minimum cost to make ‘STR’ valid.

For Example:

Minimum operations to make ‘STR’ =  “{{“ valid is 1.

In one operation, we can convert ‘{’ at index ‘1’ (0-based indexing) to ‘}’. The ‘STR’ now becomes "{}" which is a valid string.

Note:

Return -1 if it is impossible to make ‘STR’ valid.

There are ‘N’ cities numbered from 1 to ‘N’ and ‘M’ roads. Each road connectss two different cities and described as a two-way road using three integers (‘U’, ‘V’, ‘W’) which represents the cost ‘W’ to connect city ‘U’ and city ‘V’ together.

Now, you are supposed to find the minimum cost so that for every pair of cities, there exists a path of connections (possibly of length 1) that connects those two cities together. The cost is the sum of the connection costs used. If the task is impossible, return -1.

You are a product manager and currently leading a team to develop a new version of a product. Unfortunately, the latest version you are working on fails the quality check. Since each version is developed based on the previous version, all the versions after a bad version are also bad.

Suppose you have an array of N versions [1, 2, ..., N] and you want to find out the first bad version, which causes all the succeeding versions to be bad.

Consider we have a function isBadVersion(version), this will return whether the version is bad or not.

For an example, suppose n = 5, and version = 4 is the first bad version. So if the isBadVersion(3) returns false, isBadVersion(5) returns true and isBadVersion(4) also returns true, then the first bad version is 4.

You should minimize the number of calls to the API.

Note :

bool isBadVersion(version) returns true for all versions ‘V’ such that V > X, where X is the first bad version.

What is a view?(Learn)
What if I want the top 5 records of a table?(Learn)

You have been given a long type array/list 'arr’ of size 'n’.

It represents an elevation map wherein 'arr[i]’ denotes the elevation of the 'ith' bar.

Print the total amount of rainwater that can be trapped in these elevations.

Note :

The width of each bar is the same and is equal to 1.

Example:

Input: ‘n’ = 6, ‘arr’ = [3, 0, 0, 2, 0, 4].

Output: 10

Explanation: Refer to the image for better comprehension:

Note :

You don't need to print anything. It has already been taken care of. Just implement the given function.