Question about bottom-up segment tree lazy propagation

Revision en1, by sigmamale, 2022-08-08 18:41:02

Hi. I am reading Efficient and easy segment trees(bottom-up approach) and I solved a problem "Assignment to Segment" from edu(the problem is about interval assign). But I can't prove why it's sufficient to propagate only parents of l and r - 1. Can anybody help me to prove it? Problem link

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en1 sigmamale 2022-08-08 18:41:02 1699 Initial revision (published)