数据结构练习（26）在字符串中删除特定的字符

http://zhedahht.blog.163.com/blog/static/25411174200801931426484/

思路：

关于删除字符处理的特别巧妙，双指针移动的方法，最终时间复杂度为O(n).

需要注意的一点是：最后不能忘记给src字符串加上'\0'

#include <iostream>

#include <cstring>

using namespace std;



void DeleteChars(char *src, const char *dst)

{

    if (!src || !dst)

        return;



    const int hashsize = 256;

    int hash[hashsize];

    memset(hash, 0, sizeof(hash));



    const char *p = dst;

    while (*p != '\0')

    {

        hash[*p] = 1;

        ++p;

    }



    char *pfast = src;

    char *pslow = src;



    while (*pfast != '\0')

    {

        if (hash[*pfast] != 1)

        {

            *pslow = *pfast;

            ++pslow;

        }

        ++pfast;

    }

    *pslow = '\0';

}



int main()

{

    char s1[100] = "They are students.";

    char s2[100] = "aeiou";

    DeleteChars(s1, s2);

    return 0;

}