No.3608 Golden Steiner Tree
Problem Statement
Let $\varphi = \dfrac{1+\sqrt{5}}{2}$.
You are given positive integers $N, R, B$.
Add edges to an undirected graph with vertices $1, 2, \dots, N$ according to the following conditions.
- For every integer $i$ between $1$ and $N$, inclusive, perform the following operations.
- If $1 \le \left\lfloor i \varphi \right\rfloor \le N$, add a red edge of weight $R$ between vertex $i$ and vertex $\left\lfloor i \varphi \right\rfloor$.
- If $1 \le \left\lfloor i \varphi^2 \right\rfloor \le N$, add a blue edge of weight $B$ between vertex $i$ and vertex $\left\lfloor i \varphi^2 \right\rfloor$.
Initially, all vertices of the graph are painted black.
You are given a positive integer $Q$ and $Q$ queries. The $q$-th query is given as a pair of integers $(t_q, x_q)$, and its meaning is as follows.
- If $t_q = 1$: if vertex $x_q$ is painted white, paint it black; if it is painted black, paint it white.
- If $t_q = 2$: set the weight of the red edges to $x_q$.
- If $t_q = 3$: set the weight of the blue edges to $x_q$.
After processing each query, find the answer to the following problem.
Determine whether all white vertices can be made connected by deleting $0$ or more edges, and if so, find the minimum possible total weight of the remaining edges.
If they cannot be made connected, print-1. If there are $0$ white vertices, the answer is0.
Constraints
- All input values are integers.
- $1 \le N, Q \le 2 \times 10^5$
- $1 \le R, B \le 10^9$
- $1 \le t_q \le 3 ~ (1 \le q \le Q)$
- $1 \le x_q \le N ~ (1 \le q \le Q, t_q = 1)$
- $1 \le x_q \le 10^9 ~ (1 \le q \le Q, t_q \in \{2, 3\})$
Input
The input is given from standard input in the following format.
$N$ $R$ $B$ $Q$ $t_1$ $x_1$ $t_2$ $x_2$ $\vdots$ $t_Q$ $x_Q$
Output
Print $Q$ lines. On the $q$-th line, print the answer to the problem immediately after processing the $q$-th query.
Sample
Sample 1
Input
8 3 5 8 1 4 1 6 1 7 2 10 3 1 1 4 1 6 1 7
Output
0 3 11 25 21 21 0 0
Since $\left\lfloor 4 \varphi \right\rfloor = 6$, the answer immediately after processing the $2$nd query is $3$.
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