Codeforces Global Round 14
G
Phoenix and Odometers
Codeforces
2700
原题
← FH →
翻译中…

In Fire City, there are $n$ intersections and $m$ one-way roads. The $i$-th road goes from intersection $a_i$ to $b_i$ and has length $l_i$ miles.

翻译中…

There are $q$ cars that may only drive along those roads. The $i$-th car starts at intersection $v_i$ and has an odometer that begins at $s_i$, increments for each mile driven, and resets to $0$ whenever it reaches $t_i$. Phoenix has been tasked to drive cars along some roads (possibly none) and return them to their initial intersection with the odometer showing $0$.

翻译中…

For each car, please find if this is possible.

翻译中…

A car may visit the same road or intersection an arbitrary number of times. The odometers don't stop counting the distance after resetting, so odometers may also be reset an arbitrary number of times.

翻译中…

Input

翻译中…

The first line of the input contains two integers $n$ and $m$ ($2 \le n \le 2 \cdot 10^5$; $1 \le m \le 2 \cdot 10^5$) — the number of intersections and the number of roads, respectively.

翻译中…

Each of the next $m$ lines contain three integers $a_i$, $b_i$, and $l_i$ ($1 \le a_i, b_i \le n$; $a_i \neq b_i$; $1 \le l_i \le 10^9$) — the information about the $i$-th road. The graph is not necessarily connected. It is guaranteed that between any two intersections, there is at most one road for each direction.

翻译中…

The next line contains an integer $q$ ($1 \le q \le 2 \cdot 10^5$) — the number of cars.

翻译中…

Each of the next $q$ lines contains three integers $v_i$, $s_i$, and $t_i$ ($1 \le v_i \le n$; $0 \le s_i \lt t_i \le 10^9$) — the initial intersection of the $i$-th car, the initial number on the $i$-th odometer, and the number at which the $i$-th odometer resets, respectively.

翻译中…

Output

翻译中…

Print $q$ answers. If the $i$-th car's odometer may be reset to $0$ by driving through some roads (possibly none) and returning to its starting intersection $v_i$, print YES. Otherwise, print NO.

翻译中…

Note

翻译中…

The illustration for the first example is below:

翻译中…

image

翻译中…

In the first query, Phoenix can drive through the following cities: $1$ $\rightarrow$ $2$ $\rightarrow$ $3$ $\rightarrow$ $1$ $\rightarrow$ $2$ $\rightarrow$ $3$ $\rightarrow$ $1$. The odometer will have reset $3$ times, but it displays $0$ at the end.

翻译中…

In the second query, we can show that there is no way to reset the odometer to $0$ and return to intersection $1$.

翻译中…

In the third query, the odometer already displays $0$, so there is no need to drive through any roads.

翻译中…

Below is the illustration for the second example:

翻译中…

image

翻译中…

样例

Input #1
4 4
1 2 1
2 3 1
3 1 2
1 4 3
3
1 1 3
1 2 4
4 0 1
Output #1
YES
NO
YES
InputCopy OutputCopy
Input #2
4 5
1 2 1
2 3 1
3 1 2
1 4 1
4 3 2
2
1 2 4
4 3 5
Output #2
YES
YES
InputCopy OutputCopy
题目信息
题号
1515G
时间限制
2 s
内存限制
256 MB
标签
DFS 及类似
图论
数学
数论

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。