3855. Sum of K-Digit Numbers in a Range

LeetCodeMathDivide and ConquerCombinatoricsNumber TheoryOpen on judge ↗

You are given three integers l, r, and k. Consider all possible integers consisting of exactly k digits, where each digit is chosen independently from the integer range [l, r] (inclusive). If 0 is included in the range, leading zeros are allowed. Return an integer representing the sum of all such numbers. Since the answer may be very large, return it modulo 109 + 7. Example 1: Input:

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solution.cppC++17

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