CountDiv (Codility)

Problem Statement: CountDiv

C++ Solution

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// you can use includes, for example: // #include <algorithm> // you can write to stdout for debugging purposes, e.g. // cout << "this is a debug message" << endl; int solution(int A, int B, int K) { // write your code in C++11 (g++ 4.8.2) auto count = 0; auto start = A % K; if (start != 0) { start = (A + K) / K * K; } else { count++; start = A; } if (start > B) return 0; auto end = B % K; if (end != 0) { end = (B / K) * K; } else { count++; end = B; } count = (end - start) / K + 1; return count; }

Learnings

• Diff between B and A is not the right approach

For the input (11, 34, 17), the range i.e. B - A is 23 and dividing this by 17 gives 1. However, this is incorrect as the number 17 and 34 are divisible by 17 making the answer as 2.