String Number Summation

Problem Given a string containing digits interspersed with other characters, extract every maximal run of consecutive digits as an integer and return the sum of those integers.

Input / Output

• Input: a string s.
• Output: the integer sum of all numbers embedded in s.

Constraints

• 0 ≤ |s| ≤ 10^5.
• A "number" is a maximal run of consecutive digit characters; non-digits are separators.
• An empty string, or one with no digits, sums to 0.

Example

• "a12b3c45" → 60 (12 + 3 + 45).
• "abc" → 0; "007" → 7.