36进制与10进制之间的转换

来源：互联网发布：java获取环境变量的值编辑：程序博客网时间：2024/06/05 23:00
一些面试的算法题
import java.util.HashMap;/** * 36进制与10进制转换思路： *      一、创建HashMap类型对象用于存放数字'0'到字母'Z'36个字符值键对 *      二、 * @author Administrator * */public class Ten2Thirty {    //定义36进制数字    private static final String X36 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";    //拿到36进制转换10进制的值键对    private static HashMap<Character, Integer> thirysixToTen = createMapThirtysixToTen();    //拿到10进制转换36进制的值键对    private static HashMap<Integer,Character> tenToThirtysix = createMapTenToThirtysix();    //定义静态进制数    private static int BASE = 36;    //用来存放10转36进制的字符串    private static StringBuffer sb = new StringBuffer();    private static HashMap<Character, Integer> createMapThirtysixToTen() {        HashMap<Character, Integer> map = new HashMap<Character, Integer>();        for (int i = 0; i < X36.length(); i++) {            //0--0,... ..., Z -- 35的对应存放进去            map.put(X36.charAt(i), i);        }        return map;    }    private static HashMap<Integer, Character> createMapTenToThirtysix() {        HashMap<Integer, Character> map = new HashMap<Integer,Character>();        for (int i = 0; i < X36.length(); i ++) {            //0--0,... ..., 35 -- Z的对应存放进去            map.put(i, X36.charAt(i));        }        return map;    }    /** 36 to 10     * @param pStr 36进制字符串     * @return  十进制     */    public static int ThirtysixToDeciaml(String pStr) {        if (pStr == "") return 0;        //目标十进制数初始化为0        int deciaml = 0;        //记录次方,初始为36进制长度 -1        int power = pStr.length() - 1;        //将36进制字符串转换成char[]        char[] keys = pStr.toCharArray();        for (int i = 0; i < pStr.length(); i++) {            //拿到36进制对应的10进制数            int value = thirysixToTen.get(keys[i]);            deciaml = (int) (deciaml + value*Math.pow(BASE, power));            //执行完毕 次方自减            power --;        }        return deciaml;    }    /**10 to 36     * @param iSrc  10进制整数值     * @param pRet  将iSrc转换成36进制以后的字符串     * @return  0成功，其他失败     */    public static int DeciamlToThirtySix(int iSrc, String pRet) {        String str = DeciamlToThirtySix(iSrc);        if (str.equals(pRet)) {            return 0;        } else {            return 1;        }    }    /**     * 用递归来实现10 to 36     * @param iSrc     * @return     */    public static String DeciamlToThirtySix(int iSrc) {        //循环控制        boolean flag = true;        //定义键        int key;        //定义值        int value;        while (flag) {            key = iSrc / BASE;            value = iSrc - key*BASE;            if (key == 0) {                flag = false;                sb.append(tenToThirtysix.get(value).toString());            } else if (key != 0) {                //如果value小于进制36，说明下次递归会执行上面的语句                //而这次的循环还没有终止，所以要讲循环控制设置为false;                if (value < BASE) flag = false;                sb.append(tenToThirtysix.get(key).toString());                DeciamlToThirtySix(value);            }        }        return sb.toString();    }    public static void main(String[] args) {        int x = ThirtysixToDeciaml("2S");        String s = DeciamlToThirtySix(100);        System.out.println(s);    }}
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