LeetCode 135 - Candy problem involves distributing candies to children based on their ratings in a line, following certain rules.The problem requires each child to receive at least one candy and a child with a higher rating than adjacent child gets more.Two strategies discussed in the guide are a naive two-pass greedy approach and an optimized greedy algorithm.The optimized greedy solution reduces space complexity from O(n) to O(1) by tracking peaks, valleys, and previous candies given.Code implementations provided in C++, JavaScript, and Python demonstrate the optimized approach.Test cases cover various scenarios to validate the correctness of the implemented solutions.Key takeaways include understanding the intuition behind both approaches and the significance of optimizing space for large datasets.Overall, mastering this problem helps in grasping greedy algorithms and efficient space utilization in coding interviews and DSA practice.