空格替换

问题描述

https://www.lintcode.com/problem/space-replacement/description?_from=ladder&&fromId=6

教训：java中单引号代表char，双引号代表string

    public int replaceBlank(char[] string, int length) {

        int num=0;//konggeshu
        int i=0;
        while(i<length){
            if(string[i]==' '){
                num++;
            }
            i++;
        }
        int newnum=length+2*num;
        char []ch2=new char[newnum];
        int j=0;
        for(i=0;i<length;i++){
            if(string[i]!=' '){
                ch2[j++]=string[i];
            }else{
                ch2[j++]='%';
                ch2[j++]='2';
                ch2[j++]='0';
            }
        }
        /*
        string=Arrays.copyOf(string,length+2*num);
        i=0;
        while(i<length+2*num){
            string[i]=ch2[i];
            i++;
        }
        */
        int t=0;
        while(t<newnum){
            string[t]=ch2[t];
            t++;
        }
       // System.out.println(string);
        return length+2*num;
    }

作者：书剑江山
来源：CSDN
原文：https://blog.csdn.net/abbcbbd/article/details/51306914
版权声明：本文为博主原创文章，转载请附上博文链接！

挑战

在原字符串(字符数组)中完成替换，不适用额外空间

    public int replaceBlank(char[] string, int length) {
        if(string == null){
            return 0;
        }
        int num=0;//konggeshu
        int i=0;
        while(i<length){
            if(string[i]==' '){
                num++;
            }
            i++;
        }
        int newnum=length+2*num;
        for (int j = newnum; j >= 0; j--){
            if(string[j]!=' '){
                string[j+2*num] = string[j];
            }else{
                string[j+2*num] = '0';
                string[j+2*num-1] = '2';
                string[j+2*num-2] = '%';
                num--;
            }
        }
        return newnum;
    }