0121-best-time-to-buy-and-sell-stock.ts

function maxProfit(prices: number[]): number {
    let max = 0;
    let l = 0;
    let r = 1;

    while (r < prices.length) {
        if (prices[l] < prices[r]) {
            let profit = prices[r] - prices[l];
            if (profit > max) {
                max = profit;
            }
        } else {
            l = r;
        }
        r++;
    }

    return max;
}