【练习笔记】剑指offer-面试题4 ：替换空格

【题目】

请实现一个函数，将一个字符串中的空格替换成“%20”。例如，当字符串为We Are Happy.则经过替换之后的字符串为We%20Are%20Happy。

【答案】

public class Solution {    public String replaceSpace(StringBuffer str) {       if(null == str){           return null;       }        return str.toString().replaceAll(" ","%20");    }}

class Solution {public:    string replaceSpace(string str) {        if(str.size() == 0)            return str;        int orgStrLen = str.size();        int blankNum = 0;        int index = 0;                while(str[index] != '\0')        {            if(str[index] == ' ')                ++blankNum;            ++index;        }        if(blankNum == 0)            return str;        int newStrLen = orgStrLen + 2*blankNum;        int pNew = newStrLen - 1;        int pOld = orgStrLen - 1;        str.resize(newStrLen, '0');        while(pOld >= 0 && pNew>pOld)        {            if(str[pOld] == ' ')            {                str[pNew--] = '0';                str[pNew--] = '2';                str[pNew--] = '%';            }            else            {                str[pNew--] = str[pOld];            }            --pOld;        }        return str;    }};