1925. Count Square Sum Triples

A square triple (a,b,c) is a triple where a, b, and c are integers and a2 + b2 = c2.

Given an integer n, return the number of square triples such that 1 <= a, b, c <= n.

 

Example 1:

Input: n = 5
Output: 2
Explanation: The square triples are (3,4,5) and (4,3,5).

Example 2:

Input: n = 10
Output: 4
Explanation: The square triples are (3,4,5), (4,3,5), (6,8,10), and (8,6,10).

 

Constraints:

  • 1 <= n <= 250

1925. Count Square Sum Triples
struct Solution;

impl Solution {
    fn count_triples(n: i32) -> i32 {
        let mut res = 0;
        for a in 1..n {
            for b in a + 1..n {
                for c in b + 1..=n {
                    if a * a + b * b == c * c {
                        res += 1;
                    }
                }
            }
        }
        2 * res
    }
}

#[test]
fn test() {
    let n = 5;
    let res = 2;
    assert_eq!(Solution::count_triples(n), res);
    let n = 10;
    let res = 4;
    assert_eq!(Solution::count_triples(n), res);
}