This software implements the algorithm published in U.I. Gupta, D.T. Lee, J.-T Leung. An optimal solution for the channel-assignment problem; IEEE Transactions on Computers C-28(1979), 807-810. Citation of the authors: "Given a set of intervals (pairs of real numbers), we look at the problem of finding a minimal partition of this set such that no element of the partition contains two overlapping intervals. We exhibit a O (n log n) algorithm which is optimal. The problem has applications in LSI layout design and job scheduling". And I add that this algorithm solves also some problems in register allocation inside compilers.