leetcode 1646 - Get Maximum in Generated Array

https://leetcode.com/problems/get-maximum-in-generated-array/

You are given an integer n. An array nums of length n + 1 is generated in the following way:

nums[0] = 0
nums[1] = 1
nums[2 * i] = nums[i] when 2 <= 2 * i <= n
nums[2 * i + 1] = nums[i] + nums[i + 1] when 2 <= 2 * i + 1 <= n
Return the maximum integer in the array nums​​​.

Example 1:

Input: n = 7
Output: 3
Explanation: According to the given rules:
nums[0] = 0
nums[1] = 1
nums[(1 * 2) = 2] = nums[1] = 1
nums[(1 * 2) + 1 = 3] = nums[1] + nums[2] = 1 + 1 = 2
nums[(2 * 2) = 4] = nums[2] = 1
nums[(2 * 2) + 1 = 5] = nums[2] + nums[3] = 1 + 2 = 3
nums[(3 * 2) = 6] = nums[3] = 2
nums[(3 * 2) + 1 = 7] = nums[3] + nums[4] = 2 + 1 = 3
Hence, nums = [0,1,1,2,1,3,2,3], and the maximum is 3.
Example 2:

Input: n = 2
Output: 1
Explanation: According to the given rules, the maximum between nums[0], nums[1], and nums[2] is 1.
Example 3:

Input: n = 3
Output: 2
Explanation: According to the given rules, the maximum between nums[0], nums[1], nums[2], and nums[3] is 2.

Constraints:

0 <= n <= 100

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class Solution {
public:
int getMaximumGenerated(int n) {
if (n == 0) return 0;
if (n <= 2) return 1;

vector<int> nums(n+1);
nums[0] = 0;
nums[1] = 1;

int ans = 1;

for (int j = 2; j <= n; j++) {
int i = j / 2;
nums[j] = nums[i];

if (j % 2)
nums[j] += nums[i+1];

ans = max(ans, nums[j]);
}

return ans;
}
};