Greedy Algorithms

There are n gas stations along a circular route. The amount of gas at the i-th station is gas[i]; it costs cost[i] of gas to travel from station i to station i+1. You start with an empty tank at one station. Return the starting station's index if you can travel around the circuit once in the clockwise direction; otherwise return -1. If a solution exists, it is guaranteed to be unique.

You are given an integer array nums where you are initially at index 0. Each nums[i] represents your maximum jump length from that position. Return true if you can reach the last index, otherwise false.

There are n children standing in a line, each with a rating in ratings. You must give each child at least 1 candy, and children with a higher rating than an adjacent child must receive more candies than that neighbor. Return the minimum number of candies you need.