Megacity.java

/** https://codeforces.com/problemset/problem/424/B #binary-search #greedy */
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

public class Megacity {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int s = sc.nextInt();
    ArrayList<City> arrList = new ArrayList<>();
    int x, y, population;
    for (int i = 0; i < n; i++) {
      x = sc.nextInt();
      y = sc.nextInt();
      population = sc.nextInt();
      arrList.add(new City(x, y, population));
    }
    Collections.sort(arrList);
    int target = 1000000 - s;
    ArrayList<Integer> sumArrList = new ArrayList<>();
    sumArrList.add(arrList.get(0).population);
    int curSum = 0;
    int idx = -1;
    for (int i = 0; i < arrList.size(); i++) {
      curSum += arrList.get(i).population;
      if (curSum >= target) {
        idx = i;
        break;
      }
    }
    if (idx == -1) {
      System.out.println(-1);
    } else {
      x = arrList.get(idx).x;
      y = arrList.get(idx).y;
      double val = Math.sqrt(x * x + y * y);
      System.out.println(val);
    }
  }
}

class City implements Comparable<City> {
  int x, y, population;

  City(int x, int y, int population) {
    this.x = x;
    this.y = y;
    this.population = population;
  }

  public int compareTo(City other) {
    return (x * x + y * y - (other.x * other.x + other.y * other.y));
  }
}