GUPTA MECHANICAL

IN THIS WEBSITE I CAN TELL ALL ABOUT TECH. TIPS AND TRICKS APP REVIEWS AND UNBOXINGS ALSO TECH. NEWS .............

Friday 29 July 2022

[Solution] Sum of Product 2 CodeChef Solution 2022


Problem

For an array A of length N, let F(A) denote the sum of the product of all the subarrays of A. Formally,

F(A) = \sum_{L=1}^N \sum_{R=L}^N \left (\prod_{i=L}^R A_i\right )

For example, let A = [1, 0, 1], then there are 6 possible subarrays:

  • Subarray [1, 1] has product = 1
  • Subarray [1, 2] has product = 0
  • Subarray [1, 3] has product = 0
  • Subarray [2, 2] has product = 0
  • Subarray [2, 3] has product = 0
  • Subarray [3, 3] has product = 1

So F(A) = 1+1 = 2.

Solution Click Below:-  👉CLICK HERE👈
👇👇👇👇👇

Given a binary array A, determine the sum of F(A) over all the N! orderings of A modulo 998244353.

Note that orderings here are defined in terms of indices, not elements; which is why every array of length N has N! orderings. For example, the 3! = 6 orderings of A = [1, 0, 1] are:

  • [1, 0, 1] corresponding to indices [1, 2, 3]
  • [1, 1, 0] corresponding to indices [1, 3, 2]
  • [0, 1, 1] corresponding to indices [2, 1, 3]


  • [0, 1, 1] corresponding to indices [2, 3, 1]
  • [1, 1, 0] corresponding to indices [3, 1, 2]
  • [1, 0, 1] corresponding to indices [3, 2, 1]

Input Format

  • The first line of input will contain a single integer T, denoting the number of test cases.
  • Each test case consists of multiple lines of input.
    • The first line of each test case contains a single integer N denoting the le
    • The second line contains N space-separated integers denoting the array A.

Output Format

For each test case, output the sum of F(A) over all the N! orderings of A, modulo 998244353.

No comments:

Post a Comment