ica != owin click determine ner str ger stdio.h

The Genographic Project is a research partnership between IBM and The National Geographic Society that is analyzing DNA from hundreds of thousands of contributors to map how the Earth was populated.

As an IBM researcher, you have been tasked with writing a program that will find commonalities amongst given snippets of DNA that can be correlated with individual survey information to identify new genetic markers.

A DNA base sequence is noted by listing the nitrogen bases in the order in which they are found in the molecule. There are four bases: adenine (A), thymine (T), guanine (G), and cytosine (C). A 6-base DNA sequence could be represented as TAGACC.

Given a set of DNA base sequences, determine the longest series of bases that occurs in all of the sequences. Input Input to this problem will begin with a line containing a single integer n indicating the number of datasets. Each dataset consists of the following components:

• A single positive integer m (2 <= m <= 10) indicating the number of base sequences in this dataset.
• m lines each containing a single base sequence consisting of 60 bases.

Output For each dataset in the input, output the longest base subsequence common to all of the given base sequences. If the longest common subsequence is less than three bases in length, display the string "no significant commonalities" instead. If multiple subsequences of the same longest length exist, output only the subsequence that comes first in alphabetical order. Sample Input

3
2
GATACCAGATACCAGATACCAGATACCAGATACCAGATACCAGATACCAGATACCAGATA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
3
GATACCAGATACCAGATACCAGATACCAGATACCAGATACCAGATACCAGATACCAGATA
GATACTAGATACTAGATACTAGATACTAAAGGAAAGGGAAAAGGGGAAAAAGGGGGAAAA
GATACCAGATACCAGATACCAGATACCAAAGGAAAGGGAAAAGGGGAAAAAGGGGGAAAA
3
CATCATCATCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
ACATCATCATAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AACATCATCATTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT

Sample Output

no significant commonalities
AGATAC
CATCATCAT




感覺暴力可以，但是沒有去寫。想用kmp，但是又無從下手，就學習了一波操作。

首先暴力第一串的所有子串，然後再其他字符串裏面找是否存在。技巧之一就是從長到短枚舉。


暴力：

 1 #include<iostream>
 2 #include<stdio.h>
 3 #include<string>
 4 #include<set>
 5 #include<vector>
 6 using namespace std;
 7 vector<string> t;
 8 set<string> ss;
 9 string s;
10 int _,n;
11 
12 string fun() {
13     ss.clear();
14     string str=t[0];
15     bool flag;
16     for(int len=60;len>=3;len--) {
17         for(int ix=0;ix<=60-len;ix++) {
18             string temp=str.substr(ix,len);
19             flag=true;
20             for(int k=1;k<t.size();k++) {
21                 if(t[k].find(temp)==-1) {
22                     flag=false;
23                     break;
24                 }
25             }
26             if(flag) ss.insert(temp);
27         }
28         if(ss.size()) return *ss.begin();
29     }
30     return "no significant commonalities";
31 }
32 
33 int main() {
34    // freopen("in","r",stdin);
35     for(scanf("%d",&_);_;_--) {
36         scanf("%d",&n);
37         for(int i=0;i<n;i++) {
38             cin>>s;
39             t.push_back(s);
40         }
41         cout<<fun()<<endl;
42         t.clear();
43     }
44 
45 }

View Code

kmp思想：不需要找第一個串的所有子串，只需枚舉每一個後綴，去和其他字符串匹配就行了。其實這個匹配過程就好比所有子串進行匹配了。

 1 #include<stdio.h>
 2 #include<iostream>
 3 #include<string>
 4 #include<algorithm>
 5 #include<vector>
 6 using namespace std;
 7 int _,n,Next[61];
 8 string s,strans;
 9 vector<string> t;
10 
11 void prekmp(string s) {
12     int len=s.size();
13     int i,j;
14     j=Next[0]=-1;
15     i=0;
16     while(i<len) {
17         while(j!=-1&&s[i]!=s[j]) j=Next[j];
18         if(s[++i]==s[++j]) Next[i]=Next[j];
19         else Next[i]=j;
20     }
21 }
22 
23 int kmp(string p,string t) {
24     int len=t.size();
25     int i=0,j=0,res=-1;
26     while(i<len) {
27         while(j!=-1&&t[i]!=p[j]) j=Next[j];
28         ++i;++j;
29         res=max(res,j);
30     }
31     return res;
32 }
33 
34 
35 int main() {
36    // freopen("in","r",stdin);
37     for(scanf("%d",&_);_;_--) {
38         scanf("%d",&n);
39         for(int i=0;i<n;i++) {
40             cin>>s;
41             t.push_back(s);
42         }
43         int ans=-1;
44         string str=t[0];
45         for(int i=0;i<60;i++) {
46             string temp=str.substr(i,60-i);
47             prekmp(temp);
48             int maxx=60;
49             for(int j=1;j<t.size();j++) {
50                 maxx=min(maxx,kmp(temp,t[j]));
51             }
52             if(maxx>ans) {
53                 strans=temp.substr(0,maxx);
54                 ans=maxx;
55             } else if(maxx==ans) {
56                 string anstemp=temp.substr(0,maxx);
57                 if(anstemp<strans) strans=anstemp;
58             }
59         }
60         if(strans.size()<3) cout<<"no significant commonalities"<<‘\n‘;
61         else cout<<strans<<‘\n‘;
62         t.clear();
63     }
64 }

View Code

kuangbin專題十六 KMP&&擴展KMP POJ3080 Blue Jeans