Maximum Alternating Subsequence Sum.java

class Solution {
    public long maxAlternatingSum(int[] nums) {
        int n = nums.length;
        long dp[][] = new long[n][2];
        dp[0][0] = nums[0];
        for(int i=1;i<n;i++){
            dp[i][0] = Math.max(dp[i-1][0] , Math.max(dp[i-1][1]+nums[i] , nums[i]));
            dp[i][1] = Math.max(dp[i-1][1] , Math.max(dp[i-1][0]-nums[i] , 0));
        }
        return Math.max(dp[n-1][0] , dp[n-1][1]);
    }
}