Problem #72 MEDIUM
The Cracked Safe Combination
Microsoft Apple Number Theory Logic
Problem Statement
A combination lock has digits 0–9 on each of its four wheels. The correct combination is a 4-digit number with the following properties: the number is a palindrome (reads the same forwards and backwards), all four digits are different, the sum of all four digits is 20, and the number is divisible by 11. Find all valid combinations.
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