समस्या
Number the digits of n from the left, starting at 1. Raise each digit to the power of its position and add the results. For 352 that is 3¹ + 5² + 2³. A zero digit adds 0.
Implement digit_power_sum(n).
Input
n: A positive integer.
Output
Return the sum of the powered digits.
सीमाएँ
1 ≤ n ≤ 1,000,000,000
उदाहरण
उदाहरण 1
इनपुट:
n = 352
अपेक्षित आउटपुट:
expected = 36इनपुट:
long long n = 352;
अपेक्षित आउटपुट:
long long expected = 36;इनपुट:
long n = 352;
अपेक्षित आउटपुट:
long expected = 36;व्याख्या
3¹ + 5² + 2³ = 3 + 25 + 8 = 36.
उदाहरण 2
इनपुट:
n = 89
अपेक्षित आउटपुट:
expected = 89इनपुट:
long long n = 89;
अपेक्षित आउटपुट:
long long expected = 89;इनपुट:
long n = 89;
अपेक्षित आउटपुट:
long expected = 89;व्याख्या
8¹ + 9² = 8 + 81 = 89, the number itself.
कैसे हल करें
पहले खुद कोशिश करें, फिर एक-एक करके संकेत खोलें।
संकेत 1
Scan the number digit by digit from left to right and keep track of each digit’s position.
संकेत 2
Convert the number to a string or otherwise know the left-to-right index before combining each digit with its position.
संकेत 3
Remember that a zero digit contributes nothing, but its position still matters for the exponent count.
अपेक्षित जटिलता
O(d) time, O(1) extra space