<p>You are given an array <code>prices</code> where <code>prices[i]</code> is the price of a given stock on the <code>i<sup>th</sup></code> day.</p>

<p>You want to maximize your profit by choosing a <strong>single day</strong> to buy one stock and choosing a <strong>different day in the future</strong> to sell that stock.</p>

<p>Return <em>the maximum profit you can achieve from this transaction</em>. If you cannot achieve any profit, return <code>0</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> prices = [7,1,5,3,6,4]
<strong>Output:</strong> 5
<strong>Explanation:</strong> Buy on day 2 (price = 1) and sell on day 5 (price = 6), profit = 6-1 = 5.
Note that buying on day 2 and selling on day 1 is not allowed because you must buy before you sell.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> prices = [7,6,4,3,1]
<strong>Output:</strong> 0
<strong>Explanation:</strong> In this case, no transactions are done and the max profit = 0.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= prices.length &lt;= 10<sup>5</sup></code></li>
	<li><code>0 &lt;= prices[i] &lt;= 10<sup>4</sup></code></li>
</ul>

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
static const bool __boost = []() {
	cin.tie(nullptr);
	cout.tie(nullptr);
	return std::ios_base::sync_with_stdio(false);
	}();


const size_t BUFFER_SIZE = 0x6fafffff;
alignas(std::max_align_t) char buffer[BUFFER_SIZE];
size_t buffer_pos = 0;
void* operator new(size_t size) {
	constexpr std::size_t alignment = alignof(std::max_align_t); // Default maximum alignment
	size_t padding = (alignment - (buffer_pos % alignment)) % alignment;
	size_t total_size = size + padding;
	char* aligned_ptr = &buffer[buffer_pos + padding];
	buffer_pos += total_size;
	return aligned_ptr;
}
void operator delete(void* ptr) {
}

// Overload the delete[] operator to do nothing
void operator delete[](void* ptr) {}

#include <execution>

class Solution {
public:
    int maxProfit(vector<int>& prices) {
        if (prices.empty())
            return 0;

        int n = prices.size();
        int profit = 0;
        int currMax = prices.back();
        for (int i = n - 1; i >= 0; i--)
        {
            currMax = std::max(currMax, prices[i]);
            if (currMax > prices[i])
                profit = std::max(profit, currMax - prices[i]);
        }

        return profit;
    }
};
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