F. Forests in Danger

Codeforces

IDCF10234F

Time3000ms

Memory256MB

Difficulty—

English · Original

Formal · Original

The complete problemset is available on http://maratona.ime.usp.br/primfase19/provas/competicao/maratona_en.pdf [samples]

**Definitions** Let $ n \in \mathbb{Z} $ be the length of the sequence. Let $ A = (a_1, a_2, \dots, a_n) $ be a sequence of integers, where $ a_i \in \mathbb{Z} $ for all $ i \in \{1, \dots, n\} $. A *subsegment* is defined as a contiguous subsequence $ (a_i, a_{i+1}, \dots, a_j) $ for $ 1 \leq i \leq j \leq n $. Let $ P(i,j) = \prod_{k=i}^{j} a_k $ denote the product of the subsegment from index $ i $ to $ j $. **Constraints** 1. $ 1 \leq n \leq 2 \cdot 10^5 $ 2. $ -10^9 \leq a_i \leq 10^9 $ for all $ i \in \{1, \dots, n\} $ **Objective** Compute the following three values: - $ N_{\text{neg}} = \left| \left\{ (i,j) \mid 1 \leq i \leq j \leq n,\ P(i,j) < 0 \right\} \right| $ - $ N_{\text{zero}} = \left| \left\{ (i,j) \mid 1 \leq i \leq j \leq n,\ P(i,j) = 0 \right\} \right| $ - $ N_{\text{pos}} = \left| \left\{ (i,j) \mid 1 \leq i \leq j \leq n,\ P(i,j) > 0 \right\} \right| $ Output: $ N_{\text{neg}},\ N_{\text{zero}},\ N_{\text{pos}} $

API Response (JSON)

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