用C++写的 Levenshtein 算法实现

　　前一阵子在博客园搜到有介绍这个好的算法（一个快速、高效的Levenshtein算法实现），今天想起来就把它写了一下。

#include<iostream>
#include<string>
#include<vector>
#include<conio.h>
#include<istream>

int min3(int a,int b,int c){
    if(a < b){
        return a < c?a:c;
    }
    else{
        return b < c?b:c;
    }
}
int main()
{
    std::string str1,str2;
    std::vector<int> v1;
    std::vector<int> v2;

    //输入要比较的两个字符串
    std::cout<<"input a string:";
    getline(std::cin,str1);
    std::cout<<"input another string:";
    getline(std::cin,str2);

    //交换使str1是短的字符串
    if(str1.length() > str2.length()){
        std::string temp = str1;
        str1 = str2;
        str2 = temp;
    }

    //内外循环次数
    int outTimes = str1.length();
    int innerTimes = str2.length();

    //初始化v1，v2
    for(int i = 0;i <= innerTimes; ++ i){
        v1.push_back(i);
        v2.push_back(0);
    }

    for(int i = 0;i < outTimes; ++ i){
        v2.at(0) = i + 1;
        for(int j = 0;j < innerTimes; ++ j){
            //如果不相等，编辑代价为1
            //找出v1[j+1],v1[j],v2[2]中最小的数，按情况赋给v2[j+1]
            if(str1.at(i) != str2.at(j)){
                v2.at(j + 1) = min3(v1.at(j + 1),v1.at(j),v2.at(j)) + 1;
            }
            //相等则编辑代价为0
            else if(str1.at(i) == str2.at(j)){
                v2.at(j + 1) = min3(v1.at(j + 1),v1.at(j),v2.at(j));
            }
        }

        //v1，v2逐次向右平移
        v1.assign(v2.begin(),v2.end());
    }

    //v2的最后一个元素即为距离
    int changTimes = v2.at(innerTimes);
    std::cout<<"\nthe distance of two string is "<<changTimes;

    getch();
}