Description
Solutions
Sum of All Values
🔥 FULLTIME

A school in HackerLand organized a scholarship exam with this interesting mathematics problem on addition.

Given a string num that consists of digits ('0' to '9'), a '+' can be inserted between its characters. No adjacent '+' characters are allowed. The value of the expression is then evaluated. Find the sum of the values of all possible expressions after inserting '+' characters any number of times (possibly zero). Since the answer can be large, return the value modulo (10^9 + 7).

Function Description

Complete the function getExpressionSums in the editor below.

getExpressionSums has the following parameter(s):

Example 1: 

Input:  num = "123"
Output: 168 
Explanation:

All possible valid expressions are shown.
      
    
        
  • "1 + 23", value = 24
    • 
        
  • "12 + 3", value = 15
    • 
        
  • "1 + 2 + 3", value = 6
    • 
        
  • "123", value = 123
    • 
      

Their sum is 24 + 15 + 6 + 123 = 168. Thus, the answer is 168 modulo (10^9 + 7) which is 168.
Constraints:
    An unknown myth for now 🥲
Thumbnail 0
Testcase
Result
Case 1

input:

output: