121 - Best Time to Buy and Sell Stock

function maxProfit(prices: number[]): number {
    let buy:number = prices[0];
    let profit: number = 0;
    for(let i = 1; i<prices.length; i++){
        if(prices[i]<buy){
            buy = prices[i]
        }else if(prices[i]-buy>profit){
            profit = prices[i]-buy
        }
    }
    return profit
};