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By elizabeth_zou_fanboi, history, 10 days ago, In English

You are given a directed graph of N nodes. Initially there are M directed edges which are given as input (these are unique and self edges are allowed). You can add a new edge (c, a) if the edges (a,b) and (b,c) exist in the graph. Find the total no of edges in the final graph (when you cannot add any more edges)

NOTE: (a,b) & (b,c) => (c,a) and NOT (a,c)

Constraint: N = 100,000, M = 100,000, TimeLimit = 2s

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By elizabeth_zou_fanboi, history, 2 weeks ago, In English

a permutation is valid only if |ai — i| != k for all 1<=i<=n. Count the number of valid permutations.

Constraints: 2 ≤ N ≤ 2000

1 ≤ K ≤ N − 1

EDIT: Thanks for the explanation from methanol.

I implemented that explanation:

cpp code

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