LC853_CarFleet.java

package practise.leetCode;

import java.util.Arrays;
import java.util.Stack;

public class LC853_CarFleet {
    public static void main(String[] args) {
        int target = 12;
        int[] position = {10,8,0,5,3}, speed = {2,4,1,1,3};
        System.out.println(carFleet(target, position, speed));
    }
    public static int carFleet(int target, int[] position, int[] speed) {
        int n = position.length;
        int[][] cars = new int[n][2];
        for (int i = 0; i < n; i++) {
            cars[i][0] = position[i];
            cars[i][1] = speed[i];
        }
        Arrays.sort(cars, (a, b) -> b[0] - a[0]);
        Stack<Double> stack = new Stack<>();
        for (int i = 0; i < n; i++) {
            double time = (double)(target - cars[i][0]) / cars[i][1];
            if (stack.isEmpty() || time > stack.peek()) {
                stack.push(time);
            }
        }
        return stack.size();
    }
}