360笔试 给定a,b字符串 求出b相对于a的相对路径

题目描述：给出一个函数：
a = “/qihoo/app/a/b/c/d/new.c”;
b = "/qihoo/app/1/2/test.c";
输出b相对于a的相对路径：
../../../../1/2/test.c

#include <iostream>
#include <string>
#include <algorithm>
#include <cstring>

using namespace std;
const int MAX = 100;

int index;// 标记下标含有'/'
int index_b;

void Path_To(string &a,string &b)
{
    int num_a = 0;
    int num_b = 0;
    int pos_a[MAX] = {0};   //记录字符串中/的位置
    int pos_b[MAX] = {0};
    for(unsigned int i=0;i<a.size();i++)
    {
        if(a[i] == '/')
        {
            pos_a[index++] = i;
            num_a++;
        }
    }
    for(unsigned int j=0;j<b.size();j++)
    {
        if(b[j] == '/')
        {
            pos_b[index_b++] = j;
            num_b++;
        }
    }
    //用于存放子字符串
    string from[num_a];
    string to[num_b];
    /** 测试输出字符'/'的位置
    for(int k = 0;k<num_a;k++)
        cout << pos_a[k] << " ";
    cout << endl;
    for(int l = 0;l<num_b;l++)
        cout << pos_b[l] << " ";
    cout << endl;
    */
    //截取子字符串
    for(int num=1;num<=num_a;num++)
    {
        from[num-1] = a.substr(pos_a[num-1]+1,pos_a[num]-pos_a[num-1]-1);
    }
    for(int num=1;num<=num_b;num++)
    {
        to[num-1] = b.substr(pos_b[num-1]+1,pos_b[num]-pos_b[num-1]-1);
    }
    /*
    for(int i=0;i<num_a;i++)
      cout << from[i] << " : ";
    cout << endl;
    for(int i=0;i<num_b;i++)
      cout << to[i] << " : ";
    cout << endl;
    */
    int flag = 0;//b字符串 有多少不同于a的

    for(int k=0;k<num_b;k++)
    {
        if(!(from[k].compare(to[k])))
        {
            flag++;
        }
    }
    //相对子字符串
    b = b.substr(pos_b[flag]+1);
    flag += (num_a-num_b);

    for(int i=0;i<flag;i++)
        cout<< "../";
    cout << b << endl;
}
int main()
{
    string a = "/qihoo/app/a/b/c/d/new.c";
    string b = "/qihoo/app/1/2/test.c";
    Path_To(a,b);
    return 0;
}