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  1. #include <iostream>
  2. #include <cmath>
  3. #include <vector>
  4. using namespace std;
  5.  
  6. int countNumberAppear(int n, int d) {
  7.     int count = 0;
  8.     for (int i = 1; i <= n; i *= 10) {
  9.         int left = n / (i * 10);
  10.         int current = (n / i) % 10;
  11.         int right = n % i;
  12.  
  13.         if (current < d) count += left * i;
  14.         else if (current == d) count += left * i + right + 1;
  15.         else count += (left + 1) * i;
  16.     }
  17.     return count;
  18. }
  19.  
  20. int count369Clap(int n) {
  21.     if (n <= 0) 
  22. 		return 0;
  23.  
  24.     return countNumberAppear(n, 3) + countNumberAppear(n, 6) + countNumberAppear(n, 9);
  25. }
  26.  
  27. int main() {
  28. 	int start = 0;
  29. 	int end = 0;
  30. 	cin >> start >> end;
  31.     cout << count369Clap(end) - count369Clap(start-1);
  32. }
  33.  
Success #stdin #stdout 0.01s 5288KB
comments (?)
stdin 
999999
10000000
stdout 
19200006
https://ideone.com/xyphif
language:
C++ (gcc 8.3)
created:
17 days ago
visibility:
public

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