Compare Numbers

来源：互联网发布：软件售后服务条款编辑：程序博客网时间：2024/06/07 10:33

比较两个数大小。。
本来是打算比版本号的。。结果读错题了。

if (!version1.matches("^\\d+\\.\\d+$")                || !version1.matches("^\\d+\\.\\d+$")){            return 0;        }

然后第二个就是转化。其实我们没必要将两个数都转化出来然后再去比，可以实时的去比。根据小数点的位置可以判断从第几位开始比。
初步方案：

public class Calu {    public static void main(String[] args) {        // TODO Auto-generated method stub        System.out.println(compareVersion("1.1", "1.2"));        System.out.println(compareVersion("0", "1.2"));        System.out.println(compareVersion("1.1", "1.1.1"));        System.out.println(compareVersion("1.1", "12.2"));        System.out.println(compareVersion("123.1", "1.2"));    }    public static int compareVersion(String version1, String version2) {        if (!version1.matches("^\\d+\\.\\d+$")                & !version2.matches("^\\d+\\.\\d+$")) {            return 0;        }        int V1_point = findpoint(version1);        int V2_point = findpoint(version2);        if (V1_point > V2_point)            return 1;        else if (V1_point < V2_point)            return -1;        else            for (int i = 0; i < version1.length() & i < version2.length(); i++) {                if (version1.charAt(i) < version2.charAt(i)) {                    return -1;                } else if (version1.charAt(i) > version2.charAt(i)) {                    return 1;                }            }                if(version1.length()>version2.length())                return 1;            else if(version1.length()<version2.length())                return -1;        return 0;    }    public static int findpoint(String ver) {        for (int i = 0; i < ver.length(); i++) {            if (ver.charAt(i) == '.')                return i;        }        return 0;    }}

第一次测试结果：好的。整数也行–
Input: “1”, “0”
Output: 0
Expected: 1
正则表达式扩展为：^\d+\.\d+|\d+$

第二次
Input: “01”, “1”
Output: -1
Expected: 0

public class Calu {    public static void main(String[] args) {        // TODO Auto-generated method stub        long startTime = System.nanoTime(); // 获取开始时间        System.out.println(compareVersion("1.2", "1.10"));        System.out.println(compareVersion("1.1", "1.0"));        System.out.println(compareVersion("01", "1"));        System.out.println(compareVersion("1", "0"));        System.out.println(compareVersion("0", "1"));        System.out.println(compareVersion("1.1", "1.2"));        System.out.println(compareVersion("0", "1.2"));        System.out.println(compareVersion("1.1", "1.1.1"));        System.out.println(compareVersion("1.1", "12.2"));        System.out.println(compareVersion("123.1", "1.2"));        System.out.println(compareVersion("123", "1"));        System.out.println(compareVersion("123", "12.4"));        long endTime = System.nanoTime(); // 获取结束时间        System.out.println("程序运行时间： " + (endTime - startTime) + "ns");        long startTime2 = System.nanoTime(); // 获取开始时间        System.out.println(compareVersion2("1.2", "1.10"));        System.out.println(compareVersion2("1.1", "1.0"));        System.out.println(compareVersion2("01", "1"));        System.out.println(compareVersion2("1", "0"));        System.out.println(compareVersion2("0", "1"));        System.out.println(compareVersion2("1.1", "1.2"));        System.out.println(compareVersion2("0", "1.2"));        System.out.println(compareVersion2("1.1", "1.1.1"));        System.out.println(compareVersion2("1.1", "12.2"));        System.out.println(compareVersion2("123.1", "1.2"));        System.out.println(compareVersion2("123", "1"));        System.out.println(compareVersion2("123", "12.4"));        long endTime2 = System.nanoTime(); // 获取结束时间        System.out.println("程序运行时间： " + (endTime2 - startTime2) + "ns");    }    public static int compareVersion2(String version1, String version2) {        double v1=0;        double v2=0;        try {             v1 = Double.parseDouble(version1);             v2 = Double.parseDouble(version2);        } catch (Exception e) {            return 0;        }        if (v1 > v2)            return 1;        else if (v2 > v1)            return -1;        return 0;    }    public static int compareVersion(String version1, String version2) {        String regex = "^\\d+\\.\\d+|\\d+$";        if (!version1.matches(regex) || !version2.matches(regex)) {            return 0;        }        int V1_point = findpoint(version1);        int V2_point = findpoint(version2);        if (V1_point > V2_point) {            return 1;        } else if (V1_point < V2_point) {            return -1;        } else {            int v1_len = Length(version1);            int v2_len = Length(version2);            boolean tempv1 = true;            boolean tempv2 = true;            for (int i = 0, j = 0; i < v1_len && i < v2_len; i++, j++) {                if (version1.charAt(i) == '0' && tempv1) {                    i++;                    continue;                }                tempv1 = false;                if (version2.charAt(j) == '0' && tempv2) {                    j++;                    continue;                }                tempv2 = false;                if (version1.charAt(i) < version2.charAt(j)) {                    return -1;                } else if (version1.charAt(i) > version2.charAt(j)) {                    return 1;                }            }            if (v1_len > v2_len)                return 1;            else if (v1_len < v2_len) {                return -1;            }        }        return 0;    }    public static int findpoint(String ver) {        int t = 0;        for (int i = 0; i < ver.length(); i++) {            if (ver.charAt(i) == '0')                t++;            else if (ver.charAt(i) == '.')                return i - t;        }        return ver.length() - t;    }    public static int Length(String ver) {        int result = 0;        for (int i = 0; i < ver.length() && ver.charAt(i) == '0'; i++) {            result++;        }        return ver.length() - result;    }}

这个运行效率不高啊。。
1
1
0
1
-1
-1
-1
0
-1
1
1
1
程序运行时间： 2467802ns
1
1
0
1
-1
-1
-1
0
-1
1
1
1
程序运行时间： 873143ns

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