剑指offer:替换空格 灰太狼 2021-06-24 16:00 374阅读 0赞 **试题:** 请实现一个函数,将一个字符串中的每个空格替换成“%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。 **代码:** public class Solution { public String replaceSpace(StringBuffer str) { StringBuffer res = new StringBuffer(); for(int i=0; i<str.toString().length(); i++){ char s = str.charAt(i); if(s == ' '){ res.append("%20"); }else{ res.append(s); } } return res.toString(); } } 利用原有的str buffer,重置长度后,从后往前遍历插入: public class Solution { public String replaceSpace(StringBuffer str) { int originalLength = str.length()-1; int numberOfBlank = 0; //int i = 0; for(char c : str.toString().toCharArray()){ if (c == ' '){ numberOfBlank++; } } int newLength = originalLength + numberOfBlank*2+1; str.setLength(newLength); newLength = newLength-1; while (originalLength >= 0 && newLength > originalLength){ if (str.charAt(originalLength) == ' '){ str.setCharAt(newLength--,'0'); str.setCharAt(newLength--,'2'); str.setCharAt(newLength--,'%'); }else{ str.setCharAt(newLength--,str.charAt(originalLength)); } originalLength--; } return str.toString(); } }
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