You have three stacks of cylinders where each cylinder has the same diameter, but they may vary in height.

EqualStacks.java

import java.io.*;
import java.util.*;
import java.util.stream.*;
import static java.util.stream.Collectors.toList;

class EqualStackResult {

    public static int equalStacks(List<Integer> h1, List<Integer> h2, List<Integer> h3) {

        int sum1 = 0, sum2 = 0, sum3 = 0;

        for(int i=0;i< h1.size();i++){
            sum1 +=h1.get(i);
        }

        for (int i=0;i<h2.size();i++){
            sum2+=h2.get(i);
        }

        for(int i=0;i<h3.size();i++){
            sum3+=h3.get(i);
        }

        while(!h1.isEmpty() && !h2.isEmpty() && !h3.isEmpty()){
            int min =  Math.min(Math.min(sum1,sum2),sum3);
            
            while (sum1 > min){
                sum1 -= h1.get(0);
                h1.remove(0);
            }
            while (sum2 > min){
                sum2 -= h2.get(0);
                h2.remove(0);
            }
            while (sum3 > min){
                sum3 -= h3.get(0);
                h3.remove(0);
            }

            if(sum1 == sum2 && sum1 == sum3)
                return sum1;
        }

        /*while(!(sum1 == sum2 && sum1 == sum3)) {
            System.out.println(sum1+" "+sum2+" "+sum3);
            int max = Integer.MIN_VALUE;
            if (sum1 >= sum2 && sum1 >= sum3) {
                max = 1;
            } else if (sum2 >= sum1 && sum2 >= sum3) {
                max = 2;
            } else if (sum3 >= sum1 && sum3 >= sum2) {
                max = 3;
            }
            //1755042 1754973 1755030

            switch (max) {
                case 1:
                    System.out.println("h1 "+h1.get(0));
                    sum1 -= h1.get(0);
                    h1.remove(0);
                    break;
                case 2:
                    System.out.println("h2 "+h2.get(0));
                    sum2 -= h2.get(0);
                    h2.remove(0);
                    break;
                case 3:
                    System.out.println("h3 "+h3.get(0));
                    sum3 -= h3.get(0);
                    h3.remove(0);
                    break;
            }
        }*/
        return 0;
    }

}

public class EqualStacks {
    public static void main(String[] args) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        String[] firstMultipleInput = bufferedReader.readLine().replaceAll("\\s+$", "").split(" ");

        int n1 = Integer.parseInt(firstMultipleInput[0]);

        int n2 = Integer.parseInt(firstMultipleInput[1]);

        int n3 = Integer.parseInt(firstMultipleInput[2]);

        List<Integer> h1 = Stream.of(bufferedReader.readLine().replaceAll("\\s+$", "").split(" "))
                .map(Integer::parseInt)
                .collect(toList());

        List<Integer> h2 = Stream.of(bufferedReader.readLine().replaceAll("\\s+$", "").split(" "))
                .map(Integer::parseInt)
                .collect(toList());

        List<Integer> h3 = Stream.of(bufferedReader.readLine().replaceAll("\\s+$", "").split(" "))
                .map(Integer::parseInt)
                .collect(toList());

        int result = EqualStackResult.equalStacks(h1, h2, h3);

        bufferedWriter.write(String.valueOf(result));
        bufferedWriter.newLine();

        bufferedReader.close();
        bufferedWriter.close();
    }
}