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#2008 - Maximum Earnings From Taxi

Problem Description

There are n points on a road you are driving your taxi on. The n points on the road are labeled from 1 to n in the direction you are going, and you want to drive from point 1 to point n to make money by picking up passengers. You cannot change the direction of the taxi.

The passengers are represented by a 0-indexed 2D integer array rides, where rides[i] = [starti, endi, tipi] denotes the ith passenger requesting a ride from point starti to point endi who is willing to give a tipi dollar tip.

For each passenger i you pick up, you earn endi - starti + tipi dollars. You may only drive at most one passenger at a time.

Given n and rides, return the maximum number of dollars you can earn by picking up the passengers optimally.

Note: You may drop off a passenger and pick up a different passenger at the same point.

Solution

/**
 * @param {number} n
 * @param {number[][]} rides
 * @return {number}
 */
var maxTaxiEarnings = function(n, rides) {
  rides.sort((a, b) => a[1] - b[1]);
  const dp = new Array(n + 1).fill(0);
  let rideIndex = 0;

  for (let point = 1; point <= n; point++) {
    dp[point] = dp[point - 1];
    while (rideIndex < rides.length && rides[rideIndex][1] === point) {
      const [start, end, tip] = rides[rideIndex];
      dp[point] = Math.max(dp[point], dp[start] + (end - start + tip));
      rideIndex++;
    }
  }

  return dp[n];
};