README_EN.md

1094. Car Pooling

中文文档

Description

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

Solutions

Python3

class Solution:
    def carPooling(self, trips: List[List[int]], capacity: int) -> bool:
        delta = [0] * 1001
        for num, start, end in trips:
            delta[start] += num
            delta[end] -= num
        cur = 0
        for num in delta:
            cur += num
            if cur > capacity:
                return False
        return True

Java

class Solution {
    public boolean carPooling(int[][] trips, int capacity) {
        int[] delta = new int[1001];
        for (int[] trip : trips) {
            int num = trip[0], start = trip[1], end = trip[2];
            delta[start] += num;
            delta[end] -= num;
        }
        int cur = 0;
        for (int num : delta) {
            cur += num;
            if (cur > capacity) {
                return false;
            }
        }
        return true;
    }
}

JavaScript

/**
 * @param {number[][]} trips
 * @param {number} capacity
 * @return {boolean}
 */
var carPooling = function (trips, capacity) {
    let delta = new Array();
    for (let trip of trips) {
        let [num, start, end] = trip;
        delta[start] = (delta[start] || 0) + num;
        delta[end] = (delta[end] || 0) - num;
    }
    let total = 0;
    for (let i = 0; i < delta.length; i++) {
        let cur = delta[i];
        if (cur == undefined) continue;
        total += cur;
        if (total > capacity) return false;
    }
    return true;
};

C++

class Solution {
public:
    bool carPooling(vector<vector<int>>& trips, int capacity) {
        vector<int> delta(1001);
        for (auto &trip : trips) {
            int num = trip[0], start = trip[1], end = trip[2];
            delta[start] += num;
            delta[end] -= num;
        }
        int cur = 0;
        for (auto &num : delta) {
            cur += num;
            if (cur > capacity) {
                return false;
            }
        }
        return true;
    }
};

Go

func carPooling(trips [][]int, capacity int) bool {
	delta := make([]int, 1010)
	for _, trip := range trips {
		num, start, end := trip[0], trip[1], trip[2]
		delta[start] += num
		delta[end] -= num
	}
	cur := 0
	for _, num := range delta {
		cur += num
		if cur > capacity {
			return false
		}
	}
	return true
}

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