Traversing from left or from right - Leetcode 140: Word Break II
The difference in runtime of 4ms is very small compared to normal system variance due to scheduling and whatever background tasks are running. I don't believe that indicates a performance benefit right vs left.

And the only difference between the two approaches (as far as I can see) is which order you iterate the string. Algorithmically speaking going right to left is equivalent to reversing the input strings and going left to right. There is no reason why that should be any faster as it's the exact same algorithm.

There maybe be a small difference due to branch prediction and cache hits in the CPU but this is because the input is slightly different and it exercises the CPU every do slightly differently but it will benefit either method randomly based on the input. The expected relative performance, however, is the same.

I'm sorry but I believe the is nothing to improve here.