Load Balancing (2016 Bronze) TLE

Problems and Contests
#1

I’m doing Load Balancing from the 2016 February contest.

import java.util.*;
import java.io.*;

public class Main {

    public static void main(String[] args) throws FileNotFoundException {
        File inputFile = new File("balancing.in");
        Scanner reader = new Scanner(inputFile);
        PrintWriter writer = new PrintWriter("balancing.out");
        int n = reader.nextInt();
        int b = reader.nextInt();
        ArrayList<Integer> xVals = new ArrayList<>();
        ArrayList<Integer> yVals = new ArrayList<>();
        int maxXVal = 0;
        int maxYVal = 0;
        for (int i = 0; i < n; i++) {
            int xVal = reader.nextInt();
            xVals.add(xVal);
            if (xVal > maxXVal) maxXVal = xVal;
            int yVal = reader.nextInt();
            yVals.add(yVal);
            if (yVal > maxYVal) maxYVal = yVal;
        }
        int minMax = findMax(0, 0, xVals, yVals);
        for (int x = 0; x < maxXVal; x += 2) {
            if (xVals.contains(x - 1) && x >= 2) {
                for (int y = 2; y < maxYVal; y += 2) {
                    if (yVals.contains(y - 1)) {
                        int max = findMax(x, y, xVals, yVals);
                        if (max < minMax) minMax = max;
                    }
                }
            } else if (x == 0) {
                for (int y = 2; y < maxYVal; y += 2) {
                    if (yVals.contains(y - 1)) {
                        int max = findMax(x, y, xVals, yVals);
                        if (max < minMax) minMax = max;
                    }
                }
            }
        }
        writer.println(minMax);
        writer.close();
        reader.close();
    }

    static int findMax(int a, int b, ArrayList<Integer> xVals, ArrayList<Integer> yVals) {
        int quadrant1 = 0;
        int quadrant2 = 0;
        int quadrant3 = 0;
        int quadrant4 = 0;
        for (int i = 0; i < xVals.size(); i++) {
            int x = xVals.get(i);
            int y = yVals.get(i);
            if (x > a) {
                if (y > b) {
                    quadrant1++;
                } else {
                    quadrant4++;
                }
            } else {
                if (y > b) {
                    quadrant2++;
                } else {
                    quadrant3++;
                }
            }
        }
        return Math.max(Math.max(quadrant1, quadrant2), Math.max(quadrant3, quadrant4));
    }

Initially, I got the first 6 test cases correct and the last 4 timed out. However, after researching a bit, I got 9 test cases right, with only the last one timing out. I implemented what I understood of the sweep line algorithm, but I wanted to know how I could make my code efficient enough for the last test case.

#2

For full credit, the time complexity of your solution shouldn’t depend on B.

#3

I know, and I have ignored B so far. However, I can’t figure out how to make the program more efficient for B to not have an effect.

#4

How do I improve my program to work regardless of B?

#5

You can check the analysis.