1921-eliminate-maximum-number-of-monsters.cpp

/*
  You are playing a video game where you are defending your city from a group of n monsters. 
  You are given a 0-indexed integer array dist of size n, where dist[i] is the initial distance in kilometers of the ith monster from the city.
  The monsters walk toward the city at a constant speed. The speed of each monster is given to you in an integer array speed of size n, 
  where speed[i] is the speed of the ith monster in kilometers per minute.
  You have a weapon that, once fully charged, can eliminate a single monster. 
  However, the weapon takes one minute to charge.The weapon is fully charged at the very start.
  You lose when any monster reaches your city. If a monster reaches the city at the exact moment the weapon is fully charged, 
  it counts as a loss, and the game ends before you can use your weapon.
  
  Return the maximum number of monsters that you can eliminate before you lose, or n if you can eliminate all the monsters before they reach the city. 

  Ex. Input: dist = [1,3,4], speed = [1,1,1]
      Output: 3
      Explanation:
      In the beginning, the distances of the monsters are [1,3,4]. You eliminate the first monster.
      After a minute, the distances of the monsters are [X,2,3]. You eliminate the second monster.
      After a minute, the distances of the monsters are [X,X,2]. You eliminate the thrid monster.
      All 3 monsters can be eliminated.

  Time  : O(N)
  Space : O(N)
*/

class Solution {
public:
    int eliminateMaximum(vector<int>& dist, vector<int>& speed) {
        vector<float> v;
         
        for(int i = 0 ; i < dist.size() ; i++)
            v.push_back((float) dist[i] / speed[i]);
            
        sort(v.begin(), v.end());
        int count = 0;
        int time = 0, i = 0;
        while(i < v.size()) {
            if(time >= v[i])
                return count;
            ++count;
            time += 1;
            ++i;
        }
        return count;
    }
};