class Solution {
    public int maxProfit(int[] prices) {
       int n = prices.length;
       int[][] dp = new int[n][2];

       for (int i = 0; i < n;i++) {
           if (i == 0) {
               dp[i][0] = 0;
               dp[i][1] = -prices[i];
               continue;
           }
           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[n-1][0];
    }
}

class Solution {
    public boolean canJump(int[] nums) {
        if (nums.length == 1) {
            return true;
        }
        int coverRange = 0;
        for (int i = 0; i <= coverRange; i++) {
            coverRange = Math.max(coverRange, i + nums[i]);
            if (coverRange >= nums.length - 1) {
                return true;
            }
        }
        return false;
    }
}

class Solution {
    public int jump(int[] nums) {
        int result = 0;
        int end = 0;
        int temp = 0;
        for (int i = 0; i <= end && end < nums.length - 1; ++i) {
            temp = Math.max(temp, i + nums[i]);
            if (i == end) {
                end = temp;
                result++;
            }
        }
        return result;
    }
}