将字符串完全反转---大公司简单面试题
http://topic.csdn.net/u/20080711/14/00183de8-5fdf-4fac-a39c-c4dc343b0de5.html?seed=1292595069
将字符串 String oldstr="I am a programmer"完全反转为"programmer a am I"，最好不用函数，自己写，当然也可以用
这样的 题目很多人写不出，真是汗啊！我是用链表实现的，但是比较繁琐，算是过关了，今天特来寻求最好的解决方案
public class splitstr {
public static void main(String args[])
{
String oldstr="I am a programmer";
String[] str = oldstr.split(" ");
String finalstr="";
for(int i=str.length-1;i>-1;i--)
{
finalstr=finalstr+str[i]+" ";
}
System.out.println(finalstr);
}
}
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String oldstr="I am a programmer";
int i= oldstr.length();
char[] tmp=new char[i];
for(int k=0;k
}
oldstr=String.valueOf(tmp);
System.out.println(oldstr);
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import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class test
{
public static void main(String args[])
{
String a = "rosewj";
StringBuffer sb = new StringBuffer();
for(int i = a.length()-1;i>=0;i-- ) {
char c = a.charAt(i);
sb.append(c);
}
System.out.println(sb);
}
}
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public class tts {
public static void main(String args[])
{
String oldstr="I am a programmer";
String[] str = oldstr.split(" ");
String finalstr="";
for(int i=str.length-1;i>-1;i--)
{
if(str[i].equalsIgnoreCase(""))
{
continue;
}
if(i==0)
{
finalstr=finalstr+str[i].trim();
continue;
}
finalstr=finalstr+str[i].trim()+" ";
}
System.out.println(finalstr);
}
}
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String str = "i am a test";
StringBuilder out = new StringBuilder(str.length());
StringBuilder field = new StringBuilder();
char[] charArray = str.toCharArray();
for(int i = charArray.length - 1; i >= 0; i --) {
if(charArray[i] != ' '){
field.insert(0, charArray[i]);
} else {
if(field.length() != 0) {
out.append(field.toString()) ;
field = new StringBuilder();
}
out.append(" ");
}
}
if(field.length() != 0) out.append(field.toString());
System.out.println(out.toString());
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int i = 0;
String oldstr=" I am a programmer";
int length = oldstr.length(); List<String> list = new ArrayList<String>();
//这是以空格开头的情况
if(oldstr.substring(0, 1).equals(" ")) {
String space = "";
int temp = 0;
for(int m = i; m < length; m++) {
if(oldstr.codePointAt(m) != 32) {
temp = m;
break;
}
}
space = oldstr.substring(i, temp);
list.add(space);
i = temp;
}
while(i < length) {
//获取空格之间的单词
int temp = 0;
Boolean bool = false;
String word = "";
for(int m = i; m < length; m++) {
if(oldstr.codePointAt(m) == 32) {
temp = m;
bool = true;
break;
}
}
if(!bool) {//说明是截取到oldstr的结尾
temp = length;
}
word = oldstr.substring(i, temp);
list.add(word);
i = temp;
bool = false;
//获取单词之间的空格
if(i < length) {
String space = "";
for(int m = i; m < length; m++) {
if(oldstr.codePointAt(m) != 32) {
temp = m;
bool = true;
break;
}
}
if(!bool) {
temp = length;
}
space = oldstr.substring(i, temp);
list.add(space);
i = temp;
}
}
String newstr = "";
for(int j = list.size() - 1; j >= 0; j--) {
newstr += list.get(j);
}
System.out.println(newstr);
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public class StringTest {
private static String convert(String str) {
if (str == null) {
return null;
}
char[] cs = str.toCharArray();
char[] cs0 = new char[cs.length];
int temp = cs.length;
for (int start = 0; start < cs.length;) {
boolean isBlank = isBlank(cs[start]);
int end = start;
for (; end < cs.length; end++) {
if (isBlank != isBlank(cs[end])) {
break;
}
}
System.arraycopy(cs, start, cs0, temp - (end - start),
(end - start));
temp -= (end - start);
start = end;
}
return String.valueOf(cs0);
}
private static boolean isBlank(char c) {
return c == ' ';
}
public static void main(String[] args) {
System.out.println(convert("1"));
}
}
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public class StringTest {
private static String convert(String str) {
if (str == null) {
return null;
}
char[] cs = str.toCharArray();
char[] cs0 = new char[cs.length];
int temp = cs.length;
for (int start = 0; start < cs.length;) {
boolean isBlank = isBlank(cs[start]);
int end = start;
for (; end < cs.length; end++) {
if (isBlank != isBlank(cs[end])) {
break;
}
}
System.arraycopy(cs, start, cs0, temp - (end - start),
(end - start));
temp -= (end - start);
start = end;
}
return String.valueOf(cs0);
}
private static boolean isBlank(char c) {
return c == ' ';
}
public static void main(String[] args) {
System.out.println(convert("1"));
}
}
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2个栈
先把整个字符串放进第1个栈
然后把第1个栈的字符一个个网外POP 同时PUSH进第2个栈 每遇到一个空格就是一个单词了
这时候把第2个栈的单词POP出来就行了,同时记得加个空格
这样依次把第1个栈内的字符处理完,楼主的要求打到了
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用正则表达式实现
- Java code
-
String oldstr = " I am a programmer " ; List < String > list = new ArrayList < String > (); String regEx1 = " [a-zA-Z]+ " ; String regEx2 = " + " ; Pattern p1 = Pattern.compile(regEx1); Pattern p2 = Pattern.compile(regEx2); Matcher m = Pattern.compile( " ^ + " ).matcher(oldstr); if (m.find()) { list.add(m.group()); oldstr = m.replaceAll( "" ); } while (oldstr.length() > 0 ) { Matcher m1 = p1.matcher(oldstr); if (m1.find()) { list.add(m1.group()); oldstr = m1.replaceFirst( "" ); } Matcher m2 = p2.matcher(oldstr); if (oldstr.length() > 0 && m2.find()) { list.add(m2.group()); oldstr = m2.replaceFirst( "" ); } } String newstr = "" ; for ( int j = list.size() - 1 ; j >= 0 ; j -- ) { newstr += list.get(j); } System.out.println(newstr);
输出结果：
programmer a am I 这里有个空格
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import java.util.ArrayList;
import java.util.Arrays;
public class StringFZ {
public static void main(String[] args)
{
String oldstr="I am a programmer";
String[]new1 =oldstr.split(" ",0);
for(int i=new1.length-1;i>=0;i--)
{
System.out.print(new1[i]+" ");
}
}
}
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public class Test {
public static void main(String[] args) {
String str = "I am a programmer";
char[] chs = str.toCharArray();
for(int i = 0, offset = 0; i < chs.length; i++) {
char h = chs[chs.length - 1];
if(h == ' ') {
offset = i;
}
for(int j = chs.length - 2; j >= offset; j--) {
chs[j + 1] = chs[j];
}
if(h == ' ') {
chs[i] = h;
offset++;
} else {
chs[offset] = h;
}
}
System.out.println(chs);
}
}
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public class convertString {
public static void main(String [] args){
char str = ' ';
String oldstr="I am a programmer";
int lenngth = oldstr.length();
StringBuffer newStr = new StringBuffer();
for(int i=0;i < lenngth ;i++){
str = oldstr.charAt(lenngth-1-i);
newStr.append(str);
}
System.out.println(newStr.toString());
}
}
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public class splitstr {
public static void main(String args[])
{
String oldstr="I am a programmer";
String[] str = oldstr. [color=#0000FF]split(" ",-1);
String finalstr="";
for(int i=str.length-1;i>-1;i--)
{
finalstr=finalstr+str[i]+" ";
}
System.out.println(finalstr);
}
}[/color]
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public class splitstr {
public static void main(String args[])
{
String oldstr="I am a programmer";
String[] str = oldstr.split(" ");
String finalstr="";
for(int i=str.length-1;i>-1;i--)
{
finalstr=finalstr+str[i]+" ";
}
System.out.println(finalstr);
}
}
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public class splitstr {
public static void main(String args[])
{
String oldstr="I am a programmer";
String[] str = oldstr.split(" ",-1);
String finalstr="";
for(int i=str.length-1;i>-1;i--)
{
finalstr=finalstr+str[i]+" ";
}
System.out.println(finalstr);
}
}
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----------------------------------------------------------------------------------------------------------------
import java.util.Iterator;
import java.util.Stack;
public class Test1 {
public static void main(String[] args) {
String oldstr="I am a programmer";
Stack<String> newStr = new Stack<String>();
String temp = "";
for (int i = 0; i < oldstr.length(); i++) {
if (i != oldstr.length() - 1 && oldstr.charAt(i) != ' ')
temp += oldstr.charAt(i);
else {
newStr.add(temp);
temp = "";
}
}
while(!newStr.empty())
System.out.print(newStr.pop() + " ");
}
}
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Java codepublic class splitstr {
public static void main(String[] args) {
String s = "i am a programmer";
String regu = "//s+";
String regu1 = "//w+";
String[] eg = s.split(regu);
String[] eg1 = s.split(regu1);
String result = "";
for(int i=eg.length-1;i>=0;i--){
result += eg[i]+eg1[i];
}
System.out.println(result);
}
}
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public static void main(String[] args) {
String s = "I am a Programmer";
int[] a = new int[100];
int i = 0, j = 1;
boolean flag = true;
a[0] = 0;
for(;i<s.length(); i++) {
if((s.charAt(i)==' ')==flag) {
a[j++] = i;
flag = !flag;
} } a[j--] = s.length();
String result = "";
while(j>=0) {
result += s.substring(a[j], a[j+1]);
j--;
}
System.out.println(result);
}
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我好奇用c++写了一个 也是可以的。。
void changeDown(char const *str)
{
char strtemp[255];
int count=0,j=0;
while(str[j++])count++;
j=0;
for (int i=count-1;i>=0;i--)
{
if (str[i]!=' ')
{
if (i==0)
{
strtemp[j++]=str[i];
j--;
while (j!=-1)
{
cout <
cout < <" ";
}
else
{
strtemp[j++]=str[i];
}
}
else//==' '
{
j--;
while (j!=-1)
{
cout <
cout < <" ";
j=0;
}
}
}
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public static void main(String []args)
{
String A = " I am a programer " ;
String [] str = A.split( " " );
for ( int i = str.length - 1 ;i >- 1 ;i -- )
{
System.out.print(str[i]);
System.out.print( " " );
}
System.out.println();
}
}
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南开一百题里面的啊，比较简单的一个题目。
- Java code
-
import java.util.Arrays; /** * 南开一百题 *对以空格或标点符号为分隔的所有单词进行倒排。 *最后处理的字符串（应不含标点符号）返回 *eg: You He Me-->Me He You * @author igogo007 * */ public class Nan003 { public static String strOL(String str) throws Exception{ StringBuffer buffer = new StringBuffer(str); int n = 0 ; // 数组长度 for ( int i = 0 ;i < buffer.length();i ++ ){ if ((buffer.charAt(i) < ' a ' || buffer.charAt(i) > ' z ' ) && (buffer.charAt(i) < ' A ' || buffer.charAt(i) > ' Z ' )){ n ++ ; } } // 定义数组 StringBuffer[] array = new StringBuffer[n + 1 ]; // 初始化数组 for ( int t = 0 ;t < n + 1 ;t ++ ){ array[t] = new StringBuffer( "" ); } // 依次存入数组 for ( int j = 0 ,x = n;j < buffer.length();j ++ ){ if ((buffer.charAt(j) < ' a ' || buffer.charAt(j) > ' z ' ) && (buffer.charAt(j) < ' A ' || buffer.charAt(j) > ' Z ' )){ x -- ; } else { array[x].append(buffer.charAt(j)); } } return Arrays.toString(array); } public static void main(String[] args) { try { System.out.println(strOL( " You He Me " )); System.out.println(strOL( " My name is abc.A BC,def is fdc " )); } catch (Exception e){ System.out.println( " 错误： " + e.getMessage()); } } }
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我用堆栈写了一个
- Java code
-
package dd; class string{ public static void main(String[] args){ String str = " I am a programer " ; String newstr = "" ; stack s = new stack( 50 ); for ( int i = 0 ;i < str.length();i ++ ){ if (str.charAt(i) == ' ' ){ if (newstr != "" ){ s.push(newstr); } s.push( " " ); newstr = "" ; } else { newstr += str.charAt(i); if (i == str.length() - 1 ){ s.push(newstr); } } } System.out.println( " 输出结果为： " ); s.pop(); } } class stack { private String items[]; int flag =- 1 ; stack( int size){ items = new String[size]; } void push(String data){ if (flag < items.length){ items[ ++ flag] = data; } else { System.out.println( " 堆栈溢出！ " ); } } void pop(){ String output = "" ; while (flag >- 1 ){ output += items[flag -- ]; } System.out.println(output); } }
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import java.util.*; public class UsingStackReverseString { public static void main (String args[]){ String str1 = " I am a programmer "; String str2 = ""; Stack stack1 = new Stack(); Stack stack2 = new Stack(); char[] strArray = str1.toCharArray(); for (int i=0; i<strArray.length; i++){ stack1.push(strArray[i]); } while (!stack1.empty()){ if (stack1.peek() == (Object)' '){ while (!stack2.empty()){ str2 += stack2.pop(); } str2 += stack1.pop(); } else{ stack2.push(stack1.pop()); } while (!stack2.empty()){ str2 += stack2.pop(); } } System.out.print(str2); } }
- Java code
-
remmargorp a ma I
用栈实现的...无论多少个空格都可以...
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我给出一个代码，大家参考
- Java code
-
public static void reverse() { String s = " i am a programmer " ; // 几个空格的数量分别为1，2，3，4个 String[] eg = s.split( " " , - 1 ); String result = "" ; for ( int i = eg.length - 1 ; i > 0 ; i -- ) { result += eg[i] + " " ; } result += eg[ 0 ]; // 这里要注意第一个字符的前面是不能增加空格的。否则就多了一个空格 System.out.println(result); }
此代码收录于： http://www.java2000.net/p7786
-------------------------------------------------------------------------------C/C++ code
- C/C++ code
-
/* Name: String Reverse Copyright: 0.99 Author: busycai Date: 31-07-08 20:10 Description: Stack Simulation(without any stardard function call). */ /* 字符串反转 输入：I am a Programmer 输出：Programmer a am I 算法：堆栈模拟 */ #include < iostream > using namespace std; void Reverse( char * str){ char stack[ 100 ]; int stkTop = - 1 , i, idx = 0 ; while (str[idx] != ' /0 ' ) idx ++ ; idx -- ; while (idx >= 0 ){ if (str[idx] != ' ' ) stack[ ++ stkTop] = str[idx]; else { for (i = stkTop; i >= 0 ; i -- ) cout << stack[i]; stkTop = - 1 ; cout << ' ' ; } idx -- ; } if (stkTop >= 0 ){ while (stkTop >= 0 ) cout << stack[stkTop -- ]; } cout << endl; } int main() { char str[ 255 ]; while (gets(str)){ Reverse(str); } return 0 ; }
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