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Formatted question description: https://leetcode.ca/all/2505.html

2505. Bitwise OR of All Subsequence Sums

Description

Given an integer array nums, return the value of the bitwise OR of the sum of all possible subsequences in the array.

A subsequence is a sequence that can be derived from another sequence by removing zero or more elements without changing the order of the remaining elements.

 

Example 1:

Input: nums = [2,1,0,3]
Output: 7
Explanation: All possible subsequence sums that we can have are: 0, 1, 2, 3, 4, 5, 6.
And we have 0 OR 1 OR 2 OR 3 OR 4 OR 5 OR 6 = 7, so we return 7.

Example 2:

Input: nums = [0,0,0]
Output: 0
Explanation: 0 is the only possible subsequence sum we can have, so we return 0.

 

Constraints:

  • 1 <= nums.length <= 105
  • 0 <= nums[i] <= 109

Solutions

  • class Solution {
    public long subsequenceSumOr(int[] nums) {
        long[] cnt = new long[64];
        long ans = 0;
        for (int v : nums) {
            for (int i = 0; i < 31; ++i) {
                if (((v >> i) & 1) == 1) {
                    ++cnt[i];
                }
            }
        }
        for (int i = 0; i < 63; ++i) {
            if (cnt[i] > 0) {
                ans |= 1l << i;
            }
            cnt[i + 1] += cnt[i] / 2;
        }
        return ans;
    }
}

  • class Solution {
public:
    long long subsequenceSumOr(vector<int>& nums) {
        vector<long long> cnt(64);
        long long ans = 0;
        for (int v : nums) {
            for (int i = 0; i < 31; ++i) {
                if (v >> i & 1) {
                    ++cnt[i];
                }
            }
        }
        for (int i = 0; i < 63; ++i) {
            if (cnt[i]) {
                ans |= 1ll << i;
            }
            cnt[i + 1] += cnt[i] / 2;
        }
        return ans;
    }
};

  • class Solution:
    def subsequenceSumOr(self, nums: List[int]) -> int:
        cnt = [0] * 64
        ans = 0
        for v in nums:
            for i in range(31):
                if (v >> i) & 1:
                    cnt[i] += 1
        for i in range(63):
            if cnt[i]:
                ans |= 1 << i
            cnt[i + 1] += cnt[i] // 2
        return ans


  • func subsequenceSumOr(nums []int) int64 {
	cnt := make([]int, 64)
	ans := 0
	for _, v := range nums {
		for i := 0; i < 31; i++ {
			if v>>i&1 == 1 {
				cnt[i]++
			}
		}
	}
	for i := 0; i < 63; i++ {
		if cnt[i] > 0 {
			ans |= 1 << i
		}
		cnt[i+1] += cnt[i] / 2
	}
	return int64(ans)
}

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