Levenshtein算法



#include <string>
#include <iostream>
using namespacestd;

int levenshtein(string str1,string str2);

void main(){
string str1,str2;
cout<<"please input a string str1:"<<endl;
cin>>str1;
cout<<"please input a string str2:"<<endl;
cin>>str2;
cout<<"change from str1 to str2 needs: "<<levenshtein(str1,str2)<<endl;
}

int levenshtein(string str1,string str2){
int n = str1.size();
int m = str2.size();
if ( n == 0)
return m;
if ( m == 0)
return n;
int **Arr = (int**)malloc( (m+1)*sizeof(int*) );
for (int i=0;i<=m;i++)
Arr[i] = (int*)malloc( (n+1)*sizeof(int) );
int cost = 0;
for(int i=0;i<=n;i++)
Arr[0][i] = i;
for(int j=0;j<=m;j++)
Arr[j][0] = j;
for(int i=1;i<=n;i++)
for(int j=1;j<=m;j++)
{
if (str1[i-1] == str2[j-1])
cost = 0;
else
cost = 1;
Arr[j][i] = Arr[j-1][i]+1<Arr[j][i-1]+1?Arr[j-1][i]+1:Arr[j][i-1] +1 ;
Arr[j][i] = Arr[j][i]<Arr[j-1][i-1]+cost?Arr[j][i]:Arr[j-1][i-1]+cost;
}
int nEdit = Arr[m][n];

for(int i=0;i<=m;i++)
free(Arr[i]);
free(Arr);

return nEdit;

}