Construction of the interval-adjacency graph. Construction of the interval-adjacency graph. Paired-end sequencing data partitions a reference genome into intervals A, B, C, and D with associated copy numbers. These intervals and the measured adjacencies are used to build an interval-adjacency graph. Deriving the appropriate multiplicities on this graph results in an Eulerian tour which reconstructs a cancer genome consistent with the input data. Here, a possible reconstruction is A-B C D C D where -B indicates that the block is in the inverse orientation from the reference genome. Another possible reconstruction is A B C D C D which results from the assignment of multiplicity 0 to some variant edges.