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| package cn.edu.xidian.sselab.hashtable; import java.util.ArrayList; import java.util.HashSet; import java.util.List; import java.util.Set; /** * * @author zhiyong wang * title: Repeated DNA Sequences * content: * All DNA is composed of a series of nucleotides abbreviated as A, C, G, and T, * for example: "ACGAATTCCG". When studying DNA, it is sometimes useful to identify repeated sequences within the DNA. * Write a function to find all the 10-letter-long sequences (substrings) * that occur more than once in a DNA molecule. * * For example, * * Given s = "AAAAACCCCCAAAAACCCCCCAAAAAGGGTTT", * Return * ["AAAAACCCCC", "CCCCCAAAAA"]. * */ public class RepeatedDNASequences { //自己很不细心，错了好几个地方（1）自己没有把思路想好，就开始动笔写代码 //（2）上来第一步没有考虑特殊情况 //(3)每次取值范围是（i,i+10）,这两个值都没有注意，直接写的（0,10） //(4)只考虑了set是否包含，没有考虑set的写入情况 //（5）没有考虑如果存在多个重复，是否要多次插入情况 public List<String> findRepeatedDNASequences(String s){ int length = s.length(); List list = new ArrayList(); if(s == null || length < 10) return list; Set set = new HashSet(); for(int i=0;i<length-9;i++){ String temp = s.substring(i, i+10); if(set.contains(temp) && !list.contains(temp)){ list.add(temp); }else{ set.add(temp); } } return list; } public static void main(String[] args) { RepeatedDNASequences r = new RepeatedDNASequences(); r.findRepeatedDNASequences("CAAAAAAAAAC"); } } |
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原文地址：http://www.cnblogs.com/wzyxidian/p/5158834.html
