// this program demonstrates how a given graph coloring problem // can be converted in linear time to a register assignment problem nat a,b,c,d,e; thread Coloring { a = 0; b = 1; a = a + b; a = 0; e = 1; a = a + e; b = 0; e = 1; b = b + e; b = 0; c = 1; b = b + c; c = 0; d = 1; c = c + d; d = 0; e = 1; d = d + e; }