字符串相似度算法（ Levenshtein Distance算法）

#include <iostream>
#include <vector>
#include <string>
using namespace std;

//算法
int ldistance(const string source,const string target)
{
//step 1

int n=source.length();
int m=target.length();
if (m==0) return n;
if (n==0) return m;
//Construct a matrix
typedef vector< vector<int> >  Tmatrix;
Tmatrix matrix(n+1);
for(int i=0; i<=n; i++)  matrix[i].resize(m+1);

//step 2 Initialize

for(int i=1;i<=n;i++) matrix[i][0]=i;
for(int i=1;i<=m;i++) matrix[0][i]=i;

//step 3
for(int i=1;i<=n;i++)
{
const char si=source[i-1];
//step 4
for(int j=1;j<=m;j++)
{

const char dj=target[j-1];
//step 5
int cost;
if(si==dj){
cost=0;
}
else{
cost=1;
}
//step 6
const int above=matrix[i-1][j]+1;
const int left=matrix[i][j-1]+1;
const int diag=matrix[i-1][j-1]+cost;
matrix[i][j]=min(above,min(left,diag));

}
}//step7
return matrix
[m];
}
int main(){
string s;
string d;
cout<<"source=";
cin>>s;
cout<<"diag=";
cin>>d;
int dist=ldistance(s,d);
cout<<"dist="<<dist<<endl;
}