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#!/bin/sh
//usr/bin/env rustc --test $0 -o kachow && ./kachow --nocapture; rm -f kachow ; exit
fn equal_group(ints: &[i32]) -> bool {
let mut counts = std::collections::HashMap::new();
for &n in ints {
*counts.entry(n).or_insert(0) += 1;
}
let frequencies: Vec<_> = counts.values().collect();
if frequencies.is_empty() || frequencies.iter().any(|&&c| c < 2) {
return false;
}
let gcd = frequencies
.iter()
.fold(**frequencies.first().unwrap(), |acc, &&x| {
fn gcd(a: usize, b: usize) -> usize {
if b == 0 {
a
} else {
gcd(b, a % b)
}
}
gcd(acc, x)
});
gcd >= 2
}
#[test]
fn example() {
assert_eq!(equal_group(&[1, 1, 2, 2, 2, 2]), true);
assert_eq!(equal_group(&[1, 1, 1, 2, 2, 2, 3, 3]), false);
assert_eq!(equal_group(&[5, 5, 5, 5, 5, 5, 7, 7, 7, 7, 7, 7]), true);
assert_eq!(equal_group(&[1, 2, 3, 4]), false);
assert_eq!(equal_group(&[8, 8, 9, 9, 10, 10, 11, 11]), true);
}
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