package question;

public class Question188 {
    public int maxProfit(int k, int[] prices) {
        if (prices == null || prices.length == 0 || k == 0) return 0;
        if (k>=prices.length/2) {
            return maxProfit(prices);
        }
        int[][][] dp = new int[prices.length][2][k + 1];
        dp[0][0][0] = 0;
        dp[0][0][1] = Integer.MIN_VALUE / 2;
        dp[0][1][0] = Integer.MIN_VALUE / 2;
        dp[0][1][1] = -prices[0];
        for (int i = 1; i < prices.length; i++) {
            dp[i][1][0] = Integer.MIN_VALUE / 2;
            dp[i][0][0] = 0;
            for (int j = 1; j <= k; j++) {
                if (j > (i + 2) / 2) {
                    dp[i][0][j] = Integer.MIN_VALUE / 2;
                    dp[i][1][j] = Integer.MIN_VALUE / 2;
                } else {
                    dp[i][0][j] = Math.max(dp[i - 1][0][j], dp[i - 1][1][j] + prices[i]);
                    dp[i][1][j] = Math.max(dp[i - 1][1][j], dp[i - 1][0][j - 1] - prices[i]);
                }
            }
        }
        int max = Integer.MIN_VALUE / 2;
        for (int i : dp[prices.length - 1][0]) {
            max = Math.max(max, i);
        }
        return max;
    }

    public int maxProfit(int[] prices) {
        int[][] dp = new int[prices.length][2];
        dp[0][0]=0;
        dp[0][1]= -prices[0];
        for (int i = 1; i < prices.length; i++) {
            dp[i][0]=Math.max(dp[i-1][0], dp[i-1][1]+prices[i]);
            dp[i][1]=Math.max(dp[i-1][1], dp[i-1][0]-prices[i]);
        }
        return dp[prices.length-1][0];
    }
}