/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public int maxSumTwoNoOverlap(int[] A, int L, int M) {
 
    // Construct prefix sum
    // This array contains sum of all contiguous elements
    for (int i = 1; i < A.length; i++) {
      A[i] = A[i - 1] + A[i];
    }
 
    // Assign initial values so we can skip 1st run in below for loop
    // Taking the default result to be the first L + M elements
    int res = A[L + M - 1];
 
    int maxL = A[L - 1];
    int maxM = A[M - 1];
 
    // Either L before M or M before L, start this loop at index L + M
    for (int i = L + M; i < A.length; i++) {
 
      // Keep track maxL so far
      // L before M: A[i - M] - A[i - M - L] is sum of L-length sub array
      maxL = Math.max(maxL, A[i - M] - A[i - M - L]);
 
      // Keep track maxM so far
      // M before L: A[i - M] - A[i - L - M] is sum of M-length sub array
      maxM = Math.max(maxM, A[i - L] - A[i - L - M]);
 
      // Keep track res so far
      // maxL + (A[i] - A[i - M]): Sum of max L-length sub array and current M-length sub array
      // maxM + (A[i] - A[i - L]): Sum of max M-length sub array and current L-length sub array
      res = Math.max(res, Math.max(maxL + (A[i] - A[i - M]), maxM + (A[i] - A[i - L])));
    }
 
    return res;
  }
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		Ideone x = new Ideone();
		int[] A = {3, 8, 1, 3, 2, 1, 8, 9, 0};
    	int L = 3;
    	int M = 2;
		System.out.println(x.maxSumTwoNoOverlap(A, L, M));
	}
}

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