Two colors

Write a program that, given an undirected graph, tells if we can paint
all vertices with only two colors, in such a way that no two neighboring
vertices have the same color.

Input

Input consists of several cases, each with the number of vertices n and
the number of edges m, followed by m pairs x y indicating an edge
between x and y. Suppose 1 ≤ n ≤ 10⁴, 0 ≤ m ≤ 5n, that vertices are
numbered from 0 to n − 1, x ≠ y, and that there is no more than one edge
between any pair x y.

Output

For every case, print “yes” if the graph is two-colorable, and “no”
otherwise.

Problem information

Author: Unknown
Translator: Salvador Roura

Generation: 2026-01-25T10:36:55.210Z

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