समस्या
Begin the sequence with 1 and 2. Each following term is the sum of the previous two. Include only even-valued terms no greater than limit, then add them.
Implement even_fibonacci_sum(limit).
Input
limit: The largest term value that may be included.
Output
Return the sum, or 0 if there are no eligible terms.
सीमाएँ
0 ≤ limit ≤ 10¹⁵. The result fits a signed 64-bit integer.
उदाहरण
इनपुट:
limit = 50
अपेक्षित आउटपुट:
expected = 44इनपुट:
long long limit = 50;
अपेक्षित आउटपुट:
long long expected = 44;इनपुट:
long limit = 50;
अपेक्षित आउटपुट:
long expected = 44;व्याख्या
The even terms are 2, 8, and 34. Their sum is 44.
इनपुट:
limit = 1
अपेक्षित आउटपुट:
expected = 0इनपुट:
long long limit = 1;
अपेक्षित आउटपुट:
long long expected = 0;इनपुट:
long limit = 1;
अपेक्षित आउटपुट:
long expected = 0;व्याख्या
The first even term is 2, which exceeds the limit.
कैसे हल करें
पहले खुद कोशिश करें, फिर एक-एक करके संकेत खोलें।
संकेत 1
You only need the even Fibonacci terms, not the entire sequence.
संकेत 2
Generate the sequence until the next term exceeds the limit and add qualifying terms.
संकेत 3
Watch the boundary when the limit itself is a Fibonacci term.
अपेक्षित जटिलता
O(log limit) time, O(1) extra space
संदर्भ
यह चुनौती CodeUtility के लिए अनुकूलित की गई है। ऊपर दिए गए स्टेटमेंट और सीमाओं का पालन करें।