1134. Armstrong Number
Given an integer n, return true if and only if it is an Armstrong number.
The k-digit number n is an Armstrong number if and only if the kth power of each digit sums to n.
Example 1:
Input: n = 153 Output: true Explanation: 153 is a 3-digit number, and 153 = 13 + 53 + 33.
Example 2:
Input: n = 123 Output: false Explanation: 123 is a 3-digit number, and 123 != 13 + 23 + 33 = 36.
Constraints:
1 <= n <= 108
Rust Solution
struct Solution;
impl Solution {
fn is_armstrong(n: i32) -> bool {
let mut x = n;
let mut k = 0;
let mut digits: Vec<i32> = vec![];
while x > 0 {
let d = x % 10;
digits.push(d);
x /= 10;
k += 1;
}
let sum: i32 = digits.iter().map(|x| x.pow(k)).sum();
sum == n
}
}
#[test]
fn test() {
assert_eq!(Solution::is_armstrong(153), true);
assert_eq!(Solution::is_armstrong(123), false);
}
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