Editorial for JDCC '15 Contest 3 P5 - Fireworks - MCPT: Mackenzie Competitive Programming Team

Editorial for JDCC '15 Contest 3 P5 - Fireworks

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Author: aurpine

Method 1

This is a classic difference array problem. Increase the total brightness by $B$ ~B~ at $A$ ~A~ and decrease it by $B$ ~B~ at $A + L$ ~A + L~.

Time Complexity: $\mathcal{O}(N)$ ~\mathcal{O}(N)~
Space complexity: $\mathcal{O}(N)$ ~\mathcal{O}(N)~

Method 2

Since there are a maximum of $10^7$ ~10^7~ seconds in a show but $10^4$ ~10^4~ fireworks, we don't need such a big array that will mainly be empty. We can use coordinate compression to speed up the program and to reduce memory usage. However, both methods pass. Use a map as the difference array.

Time Complexity: $\mathcal{O}(M\log M)$ ~\mathcal{O}(M\log M)~
Space complexity: $\mathcal{O}(M)$ ~\mathcal{O}(M)~

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