算法道论上的 In biological applications, we often want to compare the DNA of two (or more) different organisms. A strand of DNA consists of a string of molecules called bases, where the possible bases are adenine, guanine, cytosine, and thymine. Representing each of these bases by their initial letters, a strand of DNA can be expressed as a string over the finite set {A, C, G, T}. (See Appendix C for a definition of a string.) For example, the DNA of one organism may be S1= ACCGGTCGAGTGCGCGGAAGCCGGCCGAA, while the DNA of another organism may be S2 = GTCGTTCGGAATGCCGTTGCTCTGTAAA. One goal of comparing two strands of DNA is to determine how "similar" the two strands are, as some measure of how closely related the two organisms are. Similarity can be and is defined in many different ways. For example, we can say that two DNA strands are similar if one is a substring of the other. (Chapter 32 explores algorithms to solve this problem.) In our example, neither S1 nor S2 is a substring of the other. Alternatively, we could say that two strands are similar if the number of changes needed to turn one into the other is small. (Problem 15-3 looks at this notion.) Yet another way to measure the similarity of strands S1 and S2 is by finding a third strand S3 in which the bases in S3 appear in each of S1 and S2; these bases must appear in the same order, but not necessarily consecutively. The longer the strand S3 we can find, the more similar S1 and S2 are. In our example, the longest strand S3 is GTCGTCGGAAGCCGGCCGAA.
这只是我粗略的想法。就该可行。希望能帮上忙。 ^_^
In biological applications, we often want to compare the DNA of two (or more) different organisms. A strand of DNA consists of a string of molecules called bases, where the possible bases are adenine, guanine, cytosine, and thymine. Representing each of these bases by their initial letters, a strand of DNA can be expressed as a string over the finite set {A, C, G, T}. (See Appendix C for a definition of a string.) For example, the DNA of one organism may be S1= ACCGGTCGAGTGCGCGGAAGCCGGCCGAA, while the DNA of another organism may be S2 = GTCGTTCGGAATGCCGTTGCTCTGTAAA. One goal of comparing two strands of DNA is to determine how "similar" the two strands are, as some measure of how closely related the two organisms are. Similarity can be and is defined in many different ways. For example, we can say that two DNA strands are similar if one is a substring of the other. (Chapter 32 explores algorithms to solve this problem.) In our example, neither S1 nor S2 is a substring of the other. Alternatively, we could say that two strands are similar if the number of changes needed to turn one into the other is small. (Problem 15-3 looks at this notion.) Yet another way to measure the similarity of strands S1 and S2 is by finding a third strand S3 in which the bases in S3 appear in each of S1 and S2; these bases must appear in the same order, but not necessarily consecutively. The longer the strand S3 we can find, the more similar S1 and S2 are. In our example, the longest strand S3 is GTCGTCGGAAGCCGGCCGAA.
来比较？