怎么用Java把输入的两串字符串中的数字提取出来,并且将两串数字相乘输出？ 怎么用java把输入的字符串中的数字提取出来.
\u600e\u4e48\u7528Java\u628a\u8f93\u5165\u7684\u5b57\u7b26\u4e32\u4e2d\u7684\u6570\u5b57\u63d0\u53d6\u51fa\u6765\uff0c\u5e76\u4e14\u628a\u6c42\u6570\u5b57\u76f8\u52a0\u4e4b\u548c\uff1fimport java.io.*;
public class Demo1 {
public static void main(String[] args) throws Exception{
int sum=0,temp;
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
System.out.println(" \u8bf7\u8f93\u5165\uff1a ");
String s=br.ReadLine();
for(int i=0;i<s.length();i++){
temp=s.CharAt(i);
if(temp>=0&&temp<=10){sum=sum+temp;}
else{continue;}
}
System.out.println("The sum is:"+sum);
}
}
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Arrays;
public class NumberSplit {
public StringBuffer getString(String str) {
StringBuffer strbuf = new StringBuffer("t");
boolean flag = true;
for (int i = 0; i < str.length(); i++) {
char c = str.charAt(i);
// \u5224\u65ad\u662f\u5426\u662f\u6570\u5b57
if (c >= '0' && c <= '9') {
// \u5224\u65ad\u548c\u5b57\u7b26\u4e32\u4e2d\u7684\u6570\u5b57\u662f\u5426\u91cd\u590d
for (int j = 1; j < strbuf.length(); j++) {
if (c == strbuf.charAt(j)) {
// \u5982\u679c\u91cd\u590d,\u6807\u5fd7\u4f4d\u6570\u503c\u4e3afalse,\u5e76\u8df3\u51fa\u5faa\u73af;\u5426\u5219\u6807\u5fd7\u4f4d\u8bbe\u7f6e\u4e3atrue.
flag = false;
break;
} else
flag = true;
}
// \u53ea\u6709\u5728\u5373\u662f\u6570\u5b57\u53c8\u4e0d\u91cd\u590d\u7684\u60c5\u51b5\u4e0b\u624d\u5c06\u6539\u5b57\u7b26\u62fc\u63a5\u5230\u5b57\u7b26\u4e32\u4e0a.
if (flag) {
strbuf.append(c);
}
}
}
return strbuf;
}
public static void main(String args[]) throws Exception {
System.out.println("\u8bf7\u8f93\u5165\u4e00\u6bb5\u5b57\u7b26\u4e32,\u5e76\u4ee5\u56de\u8f66\u7ed3\u675f");
BufferedReader buf = new BufferedReader(
new InputStreamReader(System.in));
String str = buf.readLine();
StringBuffer strbuf = new NumberSplit().getString(str);
// \u5c06\u8fd4\u56de\u7684StringBuffer\u8f6c\u6362\u4e3a\u5b57\u7b26\u6570\u7ec4
char c[] = strbuf.deleteCharAt(0).toString().toCharArray();
// \u5bf9\u5b57\u7b26\u6570\u7ec4\u6392\u5e8f
Arrays.sort(c);
// \u8f93\u51fa\u5b57\u7b26\u6570\u7ec4
for (int i = 0; i < strbuf.length(); i++) {
System.out.print(c[i]);
}
}
}
解决方案：
使用正则表达式抽取数字子串；
使用Interger.parse将数字子串转为整数类型；
计算两个数字相乘即可；
// 字符串乘积
// 时间复杂度: O(m * n)
// 空间复杂度: O(m + n)
public String multiply(String num1, String num2) {
if(num1 == null || num2 == null
|| num1.length() == 0 || num2.length() == 0
|| num1.equals("0") || num2.equals("0")){
return "0";
}
int m = num1.length() - 1, n = num2.length() - 1;
int[] temp = new int[m + n + 2]; // 空间复杂度O(m + n)
for(int i = m; i >= 0; i-- ){ // 时间复杂度: O(m*n)
int x = num1.charAt(i) - '0';
for(int j = n; j >= 0; j--){
int y = num2.charAt(j) - '0';
temp[i + j + 1] += x*y;
}
}
for(int i = temp.length - 1; i > 0; i--){ //时间复杂度: O(n+m)
temp[i-1] += temp[i] / 10;
temp[i] = temp[i] % 10;
}
int index = temp[0] == 0 ? 1 : 0;
StringBuilder sb = new StringBuilder();// 空间复杂度 O(m + n)
for(int i = index; i < temp.length; i++){ // 时间复杂度 O(n + m)
sb.append(temp[i]);
}
return sb.toString();
}
正则表达式+BigDecimal
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