SDE - 1

You are given an integer array 'ARR' of size 'N' and an integer 'S'. Your task is to return the list of all pairs of elements such that each sum of elements of each pair equals 'S'.

Note:

Each pair should be sorted i.e the first value should be less than or equals to the second value. 

Return the list of pairs sorted in non-decreasing order of their first value. In case if two pairs have the same first value, the pair with a smaller second value should come first.

The question was based on creating REST API for an Application basically performs CRUD operation.

You are given a 2-D array 'MATRIX' of dimensions N x M, of integers. You need to return the spiral path of the matrix.

Example Of Spiral Path:

You have been given string 'S' of length 'N' that may contain duplicate alphabets. Your task is to return the count of distinct subsequences of it.

For example:

For the given string “deed” :
The possible subsequences are {“”}, {“d”}, {“e”}, {“de”}, {“e”}, {“de”}, {“ee”}, {“dee”}, {“d”}, {“dd”}, {“ed”}, {“ded”}, {“ed”}, {“ded”}, {“eed”} and {“deed”}.

As, {“d”}, {“e”}, {“de”}, {“ed”} and {“ded”} are repeated. 

The distinct subsequences are {“”}, {“d”}, {“e”}, {“de”}, {“ee”}, {“dee”}, {“dd”}, {“ed”}, {“ded”}, {“eed”} and {“deed”}

Thus, the output will be 11. 

Note:

As the answer can be large, return your answer modulo 10^9  + 7.