CF1073E Segment Sum

You are given two integers $ l $ and $ r $ ( $ l \le r $ ). Your task is to calculate the sum of numbers from $ l $ to $ r $ (including $ l $ and $ r $ ) such that each number contains at most $ k $ different digits, and print this sum modulo $ 998244353 $ . For example, if $ k = 1 $ then you have to calculate all numbers from $ l $ to $ r $ such that each number is formed using only one digit. For $ l = 10, r = 50 $ the answer is $ 11 + 22 + 33 + 44 = 110 $ .

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For the first example the answer is just the sum of numbers from $ l $ to $ r $ which equals to $ \frac{50 \cdot 51}{2} - \frac{9 \cdot 10}{2} = 1230 $ . This example also explained in the problem statement but for $ k = 1 $ . For the second example the answer is just the sum of numbers from $ l $ to $ r $ which equals to $ \frac{2345 \cdot 2346}{2} = 2750685 $ . For the third example the answer is $ 101 + 110 + 111 + 112 + 113 + 114 + 115 + 116 + 117 + 118 + 119 + 121 + 122 + 131 + 133 + 141 + 144 + 151 = 2189 $ .