121.best-time-to-buy-and-sell-stock.java

/*
 * @lc app=leetcode id=121 lang=java
 *
 * [121] Best Time to Buy and Sell Stock
 */

// @lc code=start
class Solution {
    public int maxProfit(int[] prices) {
        //Actually, we can save the space with only two variables.
        int dp_i_0 = 0;
        int dp_i_1 = Integer.MIN_VALUE;

        for (int i = 0; i < prices.length; i++) {
            dp_i_0 = Math.max(dp_i_0, dp_i_1 + prices[i]);
            dp_i_1 = Math.max(dp_i_1, -prices[i]);
        }
        return dp_i_0;
    }
}
// @lc code=end