Package g2201_2300.s2281_sum_of_total_strength_of_wizards

Class Solution

java.lang.Object
g2201_2300.s2281_sum_of_total_strength_of_wizards.Solution
public class Solution extends java.lang.Object
2281 - Sum of Total Strength of Wizards.

Hard

As the ruler of a kingdom, you have an army of wizards at your command.

You are given a 0-indexed integer array strength, where strength[i] denotes the strength of the ith wizard. For a contiguous group of wizards (i.e. the wizards’ strengths form a subarray of strength), the total strength is defined as the product of the following two values:

  • The strength of the weakest wizard in the group.
  • The total of all the individual strengths of the wizards in the group.

Return the sum of the total strengths of all contiguous groups of wizards. Since the answer may be very large, return it modulo 109 + 7.

A subarray is a contiguous non-empty sequence of elements within an array.

Example 1:

Input: strength = [1,3,1,2]

Output: 44

Explanation: The following are all the contiguous groups of wizards:

  • [1] from [1 ,3,1,2] has a total strength of min([1]) * sum([1]) = 1 * 1 = 1

  • [3] from [1, 3 ,1,2] has a total strength of min([3]) * sum([3]) = 3 * 3 = 9

  • [1] from [1,3, 1 ,2] has a total strength of min([1]) * sum([1]) = 1 * 1 = 1

  • [2] from [1,3,1, 2 ] has a total strength of min([2]) * sum([2]) = 2 * 2 = 4

  • [1,3] from [1,3 ,1,2] has a total strength of min([1,3]) * sum([1,3]) = 1 * 4 = 4

  • [3,1] from [1, 3,1 ,2] has a total strength of min([3,1]) * sum([3,1]) = 1 * 4 = 4

  • [1,2] from [1,3, 1,2 ] has a total strength of min([1,2]) * sum([1,2]) = 1 * 3 = 3

  • [1,3,1] from [1,3,1 ,2] has a total strength of min([1,3,1]) * sum([1,3,1]) = 1 * 5 = 5

  • [3,1,2] from [1, 3,1,2 ] has a total strength of min([3,1,2]) * sum([3,1,2]) = 1 * 6 = 6

  • [1,3,1,2] from [1,3,1,2 ] has a total strength of min([1,3,1,2]) * sum([1,3,1,2]) = 1 * 7 = 7

The sum of all the total strengths is 1 + 9 + 1 + 4 + 4 + 4 + 3 + 5 + 6 + 7 = 44.

Example 2:

Input: strength = [5,4,6]

Output: 213

Explanation: The following are all the contiguous groups of wizards:

  • [5] from [5 ,4,6] has a total strength of min([5]) * sum([5]) = 5 * 5 = 25

  • [4] from [5, 4 ,6] has a total strength of min([4]) * sum([4]) = 4 * 4 = 16

  • [6] from [5,4, 6 ] has a total strength of min([6]) * sum([6]) = 6 * 6 = 36

  • [5,4] from [5,4 ,6] has a total strength of min([5,4]) * sum([5,4]) = 4 * 9 = 36

  • [4,6] from [5, 4,6 ] has a total strength of min([4,6]) * sum([4,6]) = 4 * 10 = 40

  • [5,4,6] from [5,4,6 ] has a total strength of min([5,4,6]) * sum([5,4,6]) = 4 * 15 = 60

The sum of all the total strengths is 25 + 16 + 36 + 36 + 40 + 60 = 213.

Constraints:

  • 1 <= strength.length <= 105
  • 1 <= strength[i] <= 109

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    totalStrength(int[] nums)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • totalStrength

      public int totalStrength(int[] nums)