1354 - Construct Target Array With Multiple Sums

Description (leetcode)

You are given an array target of n integers. From a starting array arr consisting of n 1′s, you may perform the following procedure :

• let x be the sum of all elements currently in your array.
• choose index i, such that 0 <= i < n and set the value of arr at index i to x.
• You may repeat this procedure as many times as needed.

Return true if it is possible to construct the target array from arr, otherwise, return false.

Example 1:

Input: target = [9,3,5]

Output: true

Explanation: Start with arr = [1, 1, 1]

[1, 1, 1], sum = 3 choose index 1

[1, 3, 1], sum = 5 choose index 2

[1, 3, 5], sum = 9 choose index 0

[9, 3, 5] Done

Example 2:

Input: target = [1,1,1,2]

Output: false

Explanation: Impossible to create target array from [1,1,1,1].

Example 3:

Input: target = [8,5]

Output: true

Constraints:

• n == target.length
• 1 <= n <= 5 * 10⁴
• 1 <= target[i] <= 10⁹

submission

impl Solution {
    pub fn is_possible(target: Vec<i32>) -> bool {
        let mut heap = target
            .into_iter()
            .map(|m| m as i64)
            .collect::<std::collections::BinaryHeap<_>>();
        let mut sum: i64 = heap.iter().copied().sum();
        while let Some(mut m) = heap.pop() {
            if m == 1 {
                return true;
            }
            let rest = sum - m;
            if rest == 0 || m <= rest {
                return false;
            }
            m = match m % rest == 0 {
                true => rest,
                false => m % rest,
            };
            sum = rest + m;
            heap.push(m);
        }
        false
    }
}