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 trips, trip[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
 

 

Constraints:

  1. trips.length <= 1000
  2. trips[i].length == 3
  3. 1 <= trips[i][0] <= 100
  4. 0 <= trips[i][1] < trips[i][2] <= 1000
  5. 1 <= capacity <= 100000

Rust Solution

struct Solution;

impl Solution {
    fn car_pooling(trips: Vec<Vec<i32>>, capacity: i32) -> bool {
        let mut pairs: Vec<(i32, i32)> = vec![];
        for trip in trips {
            pairs.push((trip[1], trip[0]));
            pairs.push((trip[2], -trip[0]));
        }
        pairs.sort_unstable();
        let mut max = 0;
        let mut count = 0;
        for pair in pairs {
            count += pair.1;
            max = max.max(count);
        }
        max <= capacity
    }
}

#[test]
fn test() {
    let trips = vec_vec_i32![[2, 1, 5], [3, 3, 7]];
    let capacity = 4;
    let res = false;
    assert_eq!(Solution::car_pooling(trips, capacity), res);
    let trips = vec_vec_i32![[2, 1, 5], [3, 3, 7]];
    let capacity = 5;
    let res = true;
    assert_eq!(Solution::car_pooling(trips, capacity), res);
    let trips = vec_vec_i32![[2, 1, 5], [3, 5, 7]];
    let capacity = 3;
    let res = true;
    assert_eq!(Solution::car_pooling(trips, capacity), res);
    let trips = vec_vec_i32![[3, 2, 7], [3, 7, 9], [8, 3, 9]];
    let capacity = 11;
    let res = true;
    assert_eq!(Solution::car_pooling(trips, capacity), res);
}

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