Graph coloring algorithm

Sanjana Urmy13CSE030

Greedy coloring algorithm

1. Choose an order for the vertices.2. Choose a list of colors , also in same order.3.In order , color each vertex using the first

available color on the list , making sure that no two adjacent vertices are the same color.

4.Continue in this way until each vertex is colored.

Welsh Powell Algorithm• Find the degree of each vertex• List the verices in order of descending valence.

Colour the first vertex in the list• Go down the sorted list and color every vertex

not connected to the colored vertices above the same color then cross out all colored vertices in the list.

• Repeat the process on the uncolored vertices with a new color-always working in descending order of degree until all vertices are colored.

Welsh Powell Algorithm: Example

K,G,I,J,A,B,F,C.

G,J,B