A method for determining the lengths of overhangs for target nucleic acids of a nucleic acid composition, wherein the method comprises: a) producing a nucleic acid library comprising combining i) a nucleic acid composition comprising target nucleic acids, wherein some or all of the target nucleic acids comprise an overhang, and ii) an oligonucleotide pool comprising oligonucleotides, wherein the oligonucleotide pool comprises oligonucleotides that comprise an overhang, some or all of the oligonucleotides comprise (i) a complementarity region capable of hybridizing to an overhang in a target nucleic acid, and (ii) a complementarity region identification polynucleotide, the oligonucleotides in the pool comprising complementarity regions include complementarity regions of different lengths, and the complementarity region identification polynucleotide is specific to one or more features of the complementarity region, wherein the one or more features comprise length of the complementarity region, under conditions in which complementarity regions in the oligonucleotides hybridize to overhangs in the target nucleic acids having a corresponding length, thereby forming hybridization products for a nucleic acid library; b) sequencing the hybridization products to generate sequence reads; c) determining the sequence of the complementarity region identification polynucleotides based on the sequencing reads; and d) determining the lengths of the overhangs for the target nucleic acids. a) producing a nucleic acid library comprising combining i) a nucleic acid composition comprising target nucleic acids, wherein some or all of the target nucleic acids comprise an overhang, and ii) an oligonucleotide pool comprising oligonucleotides, wherein the oligonucleotide pool comprises oligonucleotides that comprise an overhang, some or all of the oligonucleotides comprise (i) a complementarity region capable of hybridizing to an overhang in a target nucleic acid, and (ii) a complementarity region identification polynucleotide, the oligonucleotides in the pool comprising complementarity regions include complementarity regions of different lengths, and the complementarity region identification polynucleotide is specific to one or more features of the complementarity region, wherein the one or more features comprise length of the complementarity region, under conditions in which complementarity regions in the oligonucleotides hybridize to overhangs in the target nucleic acids having a corresponding length, thereby forming hybridization products for a nucleic acid library; i) a nucleic acid composition comprising target nucleic acids, wherein some or all of the target nucleic acids comprise an overhang, and ii) an oligonucleotide pool comprising oligonucleotides, wherein the oligonucleotide pool comprises oligonucleotides that comprise an overhang, some or all of the oligonucleotides comprise (i) a complementarity region capable of hybridizing to an overhang in a target nucleic acid, and (ii) a complementarity region identification polynucleotide, the oligonucleotides in the pool comprising complementarity regions include complementarity regions of different lengths, and the complementarity region identification polynucleotide is specific to one or more features of the complementarity region, wherein the one or more features comprise length of the complementarity region, the oligonucleotide pool comprises oligonucleotides that comprise an overhang, some or all of the oligonucleotides comprise (i) a complementarity region capable of hybridizing to an overhang in a target nucleic acid, and (ii) a complementarity region identification polynucleotide, the oligonucleotides in the pool comprising complementarity regions include complementarity regions of different lengths, and the complementarity region identification polynucleotide is specific to one or more features of the complementarity region, wherein the one or more features comprise length of the complementarity region, b) sequencing the hybridization products to generate sequence reads; c) determining the sequence of the complementarity region identification polynucleotides based on the sequencing reads; and d) determining the lengths of the overhangs for the target nucleic acids.