C++ unordered set PMR解Leetcode 874 Walking Robot Simulation

C++ unordered set PMR解Leetcode 874  Walking Robot Simulation

解Leetcode 874. Walking Robot Simulation因為constraints，只好用hashmap，C++ unordered_set是知名的慢，加上pmr可以快上幾倍 

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Solving LeetCode 874, Walking Robot Simulation, requires using a hashmap due to constraints. C++'s unordered_set is notoriously slow; adding PMR can speed it up several times.

[codes on Leetcode]https://leetcode.com/problems/walking-robot-simulation/solutions/7789910/hashset-using-pmr4ms-beats-9840-by-anwen-lzym/