There is a car with capacity empty seats. The vehicle only drives east (i.e., it cannot turn around and drive west). You are given the integer capacity and an array trips where trip[i] = [numPassengersi, fromi, toi] indicates that the ith trip has numPassengersi passengers and the locations to pick them up and drop them off are fromi and toi respectively. The locations are given as the number of kilometers due east from the car’s initial location. Return true__ if it is possible to pick up and drop off all passengers for all the given trips, or __false__ otherwise__.
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
Constraints:
1 <= trips.length <= 1000
trips[i].length == 3
1 <= numPassengersi <= 100
0 <= fromi < toi <= 1000
1 <= capacity <= 105
- code
class Solution:
def carPooling(self, trips: List[List[int]], capacity: int) -> bool:
trips.sort(key = lambda x: x[1])
curp = 0
hp = [] # min heap (position to quit, people) in the car
for p, s, e in trips:
while hp and s >= hp[0][0]: # people quit
curp -= heapq.heappop(hp)[1]
curp += p
if curp > capacity: return False
heapq.heappush(hp, (e, p))
return True
- code
class Solution:
def carPooling(self, trips: List[List[int]], capacity: int) -> bool:
timestamp = []
for p, s, e in trips:
timestamp.append([s, p])
timestamp.append([e, -p])
timestamp.sort()
used_capacity = 0
for time, passenger_change in timestamp:
used_capacity += passenger_change
if used_capacity > capacity:
return False
return True
- code #treeMap
class Solution {
public boolean carPooling(int[][] trips, int capacity) {
Map<Integer, Integer> timestamp = new TreeMap<>();
for(int[] trip: trips){
int p = trip[0], s = trip[1], e = trip[2];
int startp = timestamp.getOrDefault(s, 0) + p;
int endp = timestamp.getOrDefault(e, 0) - p;
timestamp.put(s, startp);
timestamp.put(e, endp);
}
int count = 0;
for (int p: timestamp.values()){
count += p;
if (count > capacity) return false;
}
return true;
}
}