DP #121 Best Time to Buy and Sell Stock

class Solution {
    public int maxProfit(int[] prices) {
        int n = prices.length;
        int mr = prices[n - 1];
        int mp = 0;
        for (int i = n - 2; i >= 0; i--) {
            if (prices[i] < mr) {
                int p = mr - prices[i];
                mp = Math.max(mp, p);
            } else {
                mr = prices[i];
            }
        }
        return mp;
    }

    public int arrSol(int[] prices) {
        int n = prices.length;
        int mp = 0;
        for (int i = 0; i < n - 1; i++) {
            for (int j = i + 1; j < n; j++) {
                int cp = prices[j] - prices[i];
                mp = Math.max(mp, cp);
            }
        }
        return mp;
    }
}