title: Maximum Sum Alternating Subsequence Sum
signature: class Solution {
  
      public Long maximumSumAlternatingSubsequenceSum(ArrayList<Integer> arr, Integer n) {
test_code: import static java.util.Map.entry;  
  import java.util.*;
  import java.lang.*;
  // TESTING CODE 
  // ============================================
  class QuestionEvaluator {
      public static String validateSolution(ArrayList<Integer> arr, Integer n, Long expected){
          try{
              Driver driver = new Driver();
              if (driver.run(arr, n,expected)){
                  return "PASSED";
              }
              return "FAILED";
              
          } catch (Exception exception_obj){
              return exception_obj.getClass().getSimpleName();
          }
  
      }
      public static void main(String[] args) {
          String result;
          result = validateSolution(new ArrayList<>(Arrays.asList(2, 5, 9, 15, 15, 20, 21, 26, 28, 32, 34, 38, 42, 42, 42, 46, 47, 48, 50, 54, 55, 60, 60, 61, 63, 63, 66, 74, 79, 80, 85, 91, 93)), 23, 2L);
          System.out.println(String.format("%s%s","TEST-0...",result));    
      
          result = validateSolution(new ArrayList<>(Arrays.asList(-98)), 0, -2147483648L);
          System.out.println(String.format("%s%s","TEST-1...",result));    
      
          result = validateSolution(new ArrayList<>(Arrays.asList(0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1)), 6, 0L);
          System.out.println(String.format("%s%s","TEST-2...",result));    
      
          result = validateSolution(new ArrayList<>(Arrays.asList(70, 5, 20, 22, 44, 94, 69, 89, 45, 92, 56, 58, 36, 91, 82, 95, 9, 60, 4, 34, 37, 95, 38, 47, 81, 68, 73, 15, 88, 8, 95, 28, 97, 12, 24, 5, 26, 82, 47, 88, 28, 33, 17, 28, 11, 71, 74)), 24, 1207L);
          System.out.println(String.format("%s%s","TEST-3...",result));    
      
          result = validateSolution(new ArrayList<>(Arrays.asList(-98, -96, -94, -94, -92, -86, -86, -84, -82, -68, -66, -66, -50, -48, -46, -36, -26, -8, -6, 8, 14, 16, 18, 22, 32, 48, 48, 50, 62, 70, 70, 74, 78, 78, 84, 86, 92, 94, 98)), 32, 0L);
          System.out.println(String.format("%s%s","TEST-4...",result));    
      
          result = validateSolution(new ArrayList<>(Arrays.asList(0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 1)), 5, 0L);
          System.out.println(String.format("%s%s","TEST-5...",result));    
      
          result = validateSolution(new ArrayList<>(Arrays.asList(1, 2, 8, 8, 12, 14, 19, 24, 25, 32, 36, 45, 47, 53, 54, 56, 56, 58, 59, 60, 65, 68, 86, 86, 91, 98)), 13, 1L);
          System.out.println(String.format("%s%s","TEST-6...",result));    
      
          result = validateSolution(new ArrayList<>(Arrays.asList(-94, 88, 94, 78, -34, 84, -32, 68, -72, 80)), 7, 162L);
          System.out.println(String.format("%s%s","TEST-7...",result));    
      
          result = validateSolution(new ArrayList<>(Arrays.asList(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1)), 30, 0L);
          System.out.println(String.format("%s%s","TEST-8...",result));    
      
          result = validateSolution(new ArrayList<>(Arrays.asList(76, 62, 62, 61, 63, 15, 61, 74, 50, 86, 60, 35, 91, 32, 93, 14, 52, 18, 14, 39)), 18, 832L);
          System.out.println(String.format("%s%s","TEST-9...",result));    
      
      }
  }
  
  class Driver{
      public boolean run(ArrayList<Integer> arr, Integer n, Long expected){
  
          PLACEHOLDER_CLS_NAME sol = new PLACEHOLDER_CLS_NAME();
          return validateSolution(sol.PLACEHOLDER_FN_NAME(arr, n),expected);
      }
      
      public boolean validateSolution(Long actual, Long expected){
          return actual.equals(expected);
      }
  }
  
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
source_py: def maximum_sum_alternating_subsequence_sum(arr, n):
      if (n == 1):
          return arr[0]
      dec = [0 for i in range((n + 1))]
      inc = [0 for i in range((n + 1))]
      dec[0] = inc[0] = arr[0]
      flag = 0
      for i in range(1, n):
          for j in range(i):
              if (arr[j] > arr[i]):
                  dec[i] = max(dec[i], (inc[j] + arr[i]))
                  flag = 1
              elif ((arr[j] < arr[i]) and (flag == 1)):
                  inc[i] = max(inc[i], (dec[j] + arr[i]))
      result = (- 2147483648)
      for i in range(n):
          if (result < inc[i]):
              result = inc[i]
          if (result < dec[i]):
              result = dec[i]
      return result
source_cpp: int maximum_sum_alternating_subsequence_sum(vector<int> arr, int n) {
    if ( n == 1 ) return arr [ 0 ];
    int dec [ n ];
    memset ( dec, 0, sizeof ( dec ) );
    int inc [ n ];
    memset ( inc, 0, sizeof ( inc ) );
    dec [ 0 ] = inc [ 0 ] = arr [ 0 ];
    int flag = 0;
    for ( int i = 1;
    i < n;
    i ++ ) {
      for ( int j = 0;
      j < i;
      j ++ ) {
        if ( arr [ j ] > arr [ i ] ) {
          dec [ i ] = max ( dec [ i ], inc [ j ] + arr [ i ] );
          flag = 1;
        }
        else if ( arr [ j ] < arr [ i ] && flag == 1 ) inc [ i ] = max ( inc [ i ], dec [ j ] + arr [ i ] );
      }
    }
    int result = INT_MIN;
    for ( int i = 0;
    i < n;
    i ++ ) {
      if ( result < inc [ i ] ) result = inc [ i ];
      if ( result < dec [ i ] ) result = dec [ i ];
    }
    return result;
  }