1094. Car Pooling

You are driving a vehicle that has capacity empty seats initially available for passengers.  The vehicle only drives east (ie. it cannot turn around and drive west.)

Given a list of tripstrip[i] = [num_passengers, start_location, end_location] contains information about the i-th trip: the number of passengers that must be picked up, and the locations to pick them up and drop them off.  The locations are given as the number of kilometers due east from your vehicle’s initial location.

Return true if and only if it is possible to pick up and drop off all passengers for all the given trips.

 

Example 1:

Input:

trips = [[2,1,5],[3,3,7]], capacity = 4

Output:

false

Example 2:

Input:

trips = [[2,1,5],[3,3,7]], capacity = 5

Output:

true

Example 3:

Input:

trips = [[2,1,5],[3,5,7]], capacity = 3

Output:

true

Example 4:

Input:

trips = [[3,2,7],[3,7,9],[8,3,9]], capacity = 11

Output:

true

 

Accepted  Solution in wrong PHP syntax (don’t drink and code)

<?php
class Solution {

     public $dic=[];
    /**
     * @param Integer[][] $trips
     * @param Integer $capacity
     * @return Boolean
     */
    function carPooling($trips, $capacity) {
        $max = 0;
        $sum = 0;
        $this->$dic = [];
        foreach ($trips as $c){
            if(!isset($this->$dic[$c[1]])){
                $this->$dic[$c[1]] = 0;
            }
            $this->$dic[$c[1]] += $c[0];
            $this->$dic[$c[2]] -= $c[0];
        }
        // 
        ksort($this->$dic);
    
        // Calculate least expected capacity
        foreach($this->$dic as $d){
            $sum += $d;
            if($sum > $max){
                $max  = $sum;
            }
        }
   
        return $max <= $capacity;
    }
}
?>

And Here’s the solution in my mind..

<?php
class Solution {

     public $dic=[];
    /**
     * @param Integer[][] $trips
     * @param Integer $capacity
     * @return Boolean
     */
    function carPooling($trips, $capacity) {
        $max = 0;
        $sum = 0;
        $this->dic = [];
        foreach ($trips as $c){
            if(!isset($this->dic[$c[1]])){
                $this->dic[$c[1]] = 0;
            }
            $this->dic[$c[1]] += $c[0];
            $this->dic[$c[2]] -= $c[0];
        }

        ksort($this->dic);
    
        // I'm finding the min capacity here, but it's not necessary 
        foreach($this->dic as $d){
            $sum += $d;
            if($sum > $max){
                $max  = $sum;
            }
        }
   
        return $max <= $capacity;
    }   
}

?>

 

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