3020. Find the Maximum Number of Elements in Subset

import java.util.*;
class Solution {
    public int maximumLength(int[] nums) {
        Map<Long, Integer> freq = new HashMap<>();

        for (int x : nums) {
            freq.put((long) x, freq.getOrDefault((long) x, 0) + 1);
        }

        int ans = 1;

        if (freq.containsKey(1L)) {
            int cnt = freq.get(1L);
            ans = Math.max(ans, cnt % 2 == 0 ? cnt - 1 : cnt);
        }

        for (long x : freq.keySet()) {
            if (x == 1) continue;

            long cur = x;
            int len = 0;

            while (freq.getOrDefault(cur, 0) >= 2) {
                len += 2;

                if (cur > 1000000000L / cur) {
                    break;
                }

                cur *= cur;
            }

            if (freq.getOrDefault(cur, 0) == 1) {
                len++;
            } else {
                len--;
            }

            ans = Math.max(ans, len);
        }

        return ans;
    }
}

from collections import Counter

class Solution:
    def maximumLength(self, nums: List[int]) -> int:
        freq = Counter(nums)

        ans = 1

        if 1 in freq:
            cnt = freq[1]
            ans = max(ans, cnt if cnt % 2 else cnt - 1)

        for x in list(freq.keys()):
            if x == 1:
                continue

            cur = x
            length = 0

            while freq.get(cur, 0) >= 2:
                length += 2
                cur *= cur

            if freq.get(cur, 0) == 1:
                length += 1
            else:
                length -= 1

            ans = max(ans, length)

        return ans

class Solution {
public:
    int maximumLength(vector<int>& nums) {
        unordered_map<long long, int> freq;

        for (int x : nums) {
            freq[x]++;
        }

        int ans = 1;

        if (freq.count(1)) {
            int cnt = freq[1];
            ans = max(ans, cnt % 2 ? cnt : cnt - 1);
        }

        for (auto &[x, f] : freq) {
            if (x == 1) continue;

            long long cur = x;
            int len = 0;

            while (freq[cur] >= 2) {
                len += 2;
                cur = cur * cur;
            }

            if (freq[cur] == 1)
                len += 1;
            else
                len -= 1;

            ans = max(ans, len);
        }

        return ans;
    }
};

/**
 * @param {number[]} nums
 * @return {number}
 */
var maximumLength = function(nums) {

    const freq = new Map();

    for (const x of nums) {
        freq.set(x, (freq.get(x) || 0) + 1);
    }

    let ans = 1;

    if (freq.has(1)) {
        const cnt = freq.get(1);
        ans = Math.max(ans, cnt % 2 === 0 ? cnt - 1 : cnt);
    }

    for (const x of freq.keys()) {
        if (x === 1) continue;

        let cur = x;
        let len = 0;

        while ((freq.get(cur) || 0) >= 2) {
            len += 2;
            cur = cur * cur;
        }

        if ((freq.get(cur) || 0) === 1)
            len += 1;
        else
            len -= 1;

        ans = Math.max(ans, len);
    }

    return ans;
};