#AT2041. E - MST + 1
E - MST + 1
E - MST + 1
Score : $500$ points
Problem Statement
Given is a weighted undirected connected graph $G$ with $N$ vertices and $M$ edges, which may contain self-loops and multi-edges.
The vertices are labeled as Vertex $1$, Vertex $2$, $\dots$, Vertex $N$.
The edges are labeled as Edge $1$, Edge $2$, $\ldots$, Edge $M$. Edge $i$ connects Vertex $a_i$ and Vertex $b_i$ and has a weight of $c_i$. Here, for every pair of integers $(i, j)$ such that $1 \leq i \lt j \leq M$, $c_i \neq c_j$ holds.
Process the $Q$ queries explained below.
The $i$-th query gives a triple of integers $(u_i, v_i, w_i)$. Here, for every integer $j$ such that $1 \leq j \leq M$, $w_i \neq c_j$ holds.
Let $e_i$ be an undirected edge that connects Vertex $u_i$ and Vertex $v_i$ and has a weight of $w_i$. Consider the graph $G_i$ obtained by adding $e_i$ to $G$.
It can be proved that the minimum spanning tree $T_i$ of $G_i$ is uniquely determined. Does $T_i$ contain $e_i$? Print the answer as Yes
or No
.
Note that the queries do not change $T$. In other words, even though Query $i$ considers the graph obtained by adding $e_i$ to $G$, the $G$ in other queries does not have $e_i$.
What is minimum spanning tree?
The spanning tree of $G$ is a tree with all of the vertices in $G$ and some of the edges in $G$.The minimum spanning tree of $G$ is the tree with the minimum total weight of edges among the spanning trees of $G$.
Constraints
- $2 \leq N \leq 2 \times 10^5$
- $N - 1 \leq M \leq 2 \times 10^5$
- $1 \leq a_i \leq N$ $(1 \leq i \leq M)$
- $1 \leq b_i \leq N$ $(1 \leq i \leq M)$
- $1 \leq c_i \leq 10^9$ $(1 \leq i \leq M)$
- $c_i \neq c_j$ $(1 \leq i \lt j \leq M)$
- The graph $G$ is connected.
- $1 \leq Q \leq 2 \times 10^5$
- $1 \leq u_i \leq N$ $(1 \leq i \leq Q)$
- $1 \leq v_i \leq N$ $(1 \leq i \leq Q)$
- $1 \leq w_i \leq 10^9$ $(1 \leq i \leq Q)$
- $w_i \neq c_j$ $(1 \leq i \leq Q, 1 \leq j \leq M)$
- All values in input are integers.
Input
Input is given from Standard Input in the following format:
Output
Print $Q$ lines. The $i$-th line should contain the answer to Query $i$: Yes
or No
.
5 6 3
1 2 2
2 3 3
1 3 6
2 4 5
4 5 9
3 5 8
1 3 1
3 4 7
3 5 7
Yes
No
Yes
Below, let $(u,v,w)$ denote an undirected edge that connects Vertex $u$ and Vertex $v$ and has the weight of $w$. Here is an illustration of $G$:
For example, Query $1$ considers the graph $G_1$ obtained by adding $e_1 = (1,3,1)$ to $G$. The minimum spanning tree $T_1$ of $G_1$ has the edge set $\lbrace (1,2,2),(1,3,1),(2,4,5),(3,5,8) \rbrace$, which contains $e_1$, so Yes
should be printed.
2 3 2
1 2 100
1 2 1000000000
1 1 1
1 2 2
1 1 5
Yes
No
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