21959번 - Subway 서브태스크점수다국어

Given an integer number K, generate a tree with minimum number of nodes such that there are exactly K pairs of nodes (X, Y), where X is an ancestor of Y.

The input (from the console) will contain a single integer number, K – the number of pairs with the specified property.

The output (to the console) will contain N+1 lines, representing the generated tree, the nodes being indexed from 0.

The first line will contain the number N – the number of nodes in the tree.

The following N lines will contain each 2 numbers X and T, separated by a space, with the following meaning: node T is the direct ancestor of node X. If node X doesn’t have a direct ancestor, T will have value -1.

For every test, you will get:

1. 100% points if N_participant = N_committee
2. 80% points if N_participant ∈ [N_committee+1, N_committee+2]
3. P% points if N_participant ≥ N_committee + 3, where P = (N_committee + 3) / N_participant × 50

N_committee is the minimum number of nodes that a tree with the specified property can be generated with.