Graphs (1)

Given a directed graph with $m$ vertices and $m$ arcs, we wish to know if there is a directed path between two given vertices.

Input

Input starts with $n$ i $m$ . Then follow $m$ pairs $u,v$ , with $u \ne v$ , indicating an arc from $u$ to $v$ . We have that $0\le u<n$ and $0\le v<n$ and there are no repeated arcs. Then follows, a pair $x,y$ with $0\le x<n$ and $0\le y <n$ .

Output

Write “yes” o “no” according to whether there is or not a path from $x$ to $y$ .

Problem information

Author: Jordi Petit
Translator: Jordi Petit

Generation: 2026-01-25T11:22:50.547Z