每日微软面试题——day 6（打印所有对称子串）

分类： 2.数据结构与算法2011-08-14 14:27 9595人阅读评论(15) 收藏举报

面试微软 string 测试 system distance

<以下微软面试题全来自网络>

<以下答案与分析纯属个人观点，不足之处，还望不吝指出^_^>

<出处：http://blog.csdn.net/zhanxinhang>

题：1、如何判断一个字符串是对称的？如a，aa，aba。

2、如何利用2函数找出一个字符串中的所有对称子串？

分析：

且看第一个问题判断字符串对称，有以下两种方法。

方法一、使迭代器p1指向头，p2指向尾。使p1，p2相对而行(—> | <—)，每次比较p1，p2是否相等，直到它们相遇。

方法二、使p1、p2指向中间的一个元素（如果字符串长度为偶数的话就指向中间两个相邻的元素），使它们相向而行(<— |—>)，每次比较p1，p2是否相等。直到它们一个指向头一个指向尾便结束。

（可以看出方法1明显好于方法2）

现在看第二个问题打印所有的对称子串，判断对称子串的问题我们似乎已经解决，且有以上两种方法，针对现在的情况是否两种都合适呢，确切的说不是。如果是方法一，请想象一下，如果要p1，p2一个指向子串的头一个指向子串的尾，那么至少要两层循环一层控制p1一层控制p2，还有一层循环用于判断子串是否对称，也就是说总共需要三层嵌套循环，时间复杂度指数为3。而如果选择方法二呢？两层循环就能实现，不过要适应现在这种情况需要做些修改，就是针对偶数长度的子串进行一次遍历，再针对奇数长度的子串进行一次遍历，也就是两层嵌套循环中内层有两次循环，时间复杂度指数为2。详情且看代码。

实现加测试代码：

/**
Author:花心龟
Blog：http://blog.csdn.net/zhanxinhang
**/
#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;
class App
{
typedef string::iterator Iter_t;
string m_str;
void print(Iter_t p1, Iter_t p2) //打印从p1开始到p2结束的字符
{
while(p1<=p2)
{
cout<<*p1;
p1++;
}
cout<<" | ";
}
bool isHuiwen1(Iter_t start,Iter_t end) //法1判断是否为对称子串
{
Iter_t p1 = start;
Iter_t p2 = end;
int times = (distance(p1,p2)+1) / 2; //比较次数
while(times)
{
if(*p1 != *p2)
return false;
p1++;
p2--;
times--;
}
return true;
}
bool isHuiwen2(Iter_t mid_it) //法2判断是否为对称子串
{
Iter_t p1,p2;
p1 = p2 = mid_it;
while(p1>=m_str.begin() && p2 < m_str.end())
{
if(*p1 != *p2)
break;
print(p1,p2);//打印从p1到p2的字符
p1--,p2++;
}
p1 = p2 = mid_it;
p2++; //使p2向前移动一个位置，此时p1，p2分别指向中间两个相邻位置
while(p1>=m_str.begin() && p2 < m_str.end())
{
if(*p1 != *p2)
return false;
print(p1,p2);//打印从p1到p2的字符
p1--,p2++;
}
return true;
}
void show_all_substr_of_huiwen1() //法一打印所有对称子串
{
Iter_t p2=m_str.end()-1;
Iter_t p1 = m_str.begin();
for(;p1!=m_str.end();p1++)
for(p2=p1;p2!=m_str.end();p2++)
{
if(isHuiwen1(p1,p2))
print(p1,p2);
}
}
void show_all_substr_of_huiwen2() //法二打印所有对称子串
{
Iter_t it = m_str.begin();
for(;it!=m_str.end();it++)
{
isHuiwen2(it);
}
}
public:
void run()
{
m_str="abaaba";
cout<<"测试数据为:abaaba"<<endl;
show_all_substr_of_huiwen1();
cout<<endl;
show_all_substr_of_huiwen2();
cout<<endl;
m_str="asdfie";
cout<<"测试数据为:asdfie"<<endl;
show_all_substr_of_huiwen1();
cout<<endl;
show_all_substr_of_huiwen2();
cout<<endl;
m_str="aabaa";
cout<<"测试数据为:aabaa"<<endl;
show_all_substr_of_huiwen1();
cout<<endl;
show_all_substr_of_huiwen2();
cout<<endl;
//时间比较//
m_str="this is a string for testing. aabaa alskjdfkljasdjflasdflkajsldkjfsjlakjsdlfjwoekjlakjlsdkjflsajlkdjfowieuoriuq aaddbb sldjfalkjsdlfkjasldjflajsldfjalskdjflakjsdlfkjaslkdjflajsdlfkjaslkdjflkajsdlkjflkasjdlfjaklsjdkfljaklsdjfklsajdflkjslkdjflaskjdlfkjalsdjlfkajsldfkjlaksjdfljasldjflaskjdfkasjdflaksjdkfljaskldfjlaksjdfljasldjflaksjdkljfkalsjdlkfjasldjflasjdlfjasldjfklsajdfljaskldfjlsakjdflkasjdfkl this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.make -k make -k make -k make -k make -k make -k is is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.make -k make -k make -k make -k make -k make -k is is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.make -k make -k make -k make -k make -k make -k is is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.make -k make -k make -k make -k make -k make -k is is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.make -k make -k make -k make -k make -k make -k is is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.make -k make -k make -k make -k make -k make -k is is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.make -k make -k make -k make -k make -k make -k is is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.make -k make -k make -k make -k make -k make -k is is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.make -k make -k make -k make -k make -k make -k is is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.make -k make -k make -k make -k make -k make -k is is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.make -k make -k make -k make -k make -k make -k is is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.this is a string for testing.make -k make -k make -k make -k make -k make -k end";
time_t start,record1;
cout<<"show all substr of huiwen 1:";
system("pause");
start = time(NULL);
show_all_substr_of_huiwen1();
record1 = time(NULL);
cout<<endl;
cout<<"time:"<<record1-start;
cout<<endl;
cout<<"show all substr of huiwen 2:";
system("pause");
start = time(NULL);
show_all_substr_of_huiwen2();
record1 = time(NULL);
cout<<endl;
cout<<"time:"<<record1-start;
cout<<endl;
cout<<"(可以看到打印速度明显快于上一次)";
}
};
int main()
{
App myapp;
myapp.run();
system("pause");
return 0;
}

测试结果：

各测试数据下的一二行为打印出来的所有对称字串。

按下任意键后：

以上是使用方法1打印出来的结果。

按下任意键后：

以上便是用方法2打印出来的结果。

每日微软面试题——day 6（打印所有对称子串）的更多相关文章

每日三道面试题，通往自由的道路6——JVM
茫茫人海千千万万,感谢这一秒你看到这里.希望我的面试题系列能对你的有所帮助!共勉! 愿你在未来的日子,保持热爱,奔赴山海! 每日三道面试题,成就更好自我今天我们继续聊聊JVM的话题吧! 1. 那你知 ...
《剑指offer》面试题12：打印1到最大的n位数
面试题12:打印1到最大的n位数剑指offer题目12,题目如下输入数字n,按顺序打印出1到最大的n位十进制数,比如输入3,则打印出1,2,3一直到最大的三位数999 方法一和面试题11< ...
【面试题012】打印1到最大的n位数
[面试题012]打印1到最大的n位数大数问题字符串中的每一个字符都是‘0’到‘9’之间的某一个字符,用来表示数字中的一位,因为数字最大是n位的,因此我们需要一个长度为n+1的字符串,字符串的最后 ...
【剑指offer】面试题 29. 顺时针打印矩阵
面试题 29. 顺时针打印矩阵题目描述题目:输入一个矩阵,按照从外向里以顺时针的顺序依次打印出每一个数字,例如,如果输入如下矩阵: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 ...
面试题17：打印1到最大的n位数
// 面试题17:打印1到最大的n位数 // 题目:输入数字n,按顺序打印出从1最大的n位十进制数.比如输入3,则 // 打印出1.2.3一直到最大的3位数即999. 解题思路: 首先是一个大陷阱,n ...
每日三道面试题，通往自由的道路5——JVM
茫茫人海千千万万,感谢这一秒你看到这里.希望我的面试题系列能对你的有所帮助!共勉! 愿你在未来的日子,保持热爱,奔赴山海! 每日三道面试题,成就更好自我昨天既然我们聊到了JVM,那我们继续这一个话题 ...
每日三道面试题，通往自由的道路4——JVM篇
茫茫人海千千万万,感谢这一秒你看到这里.希望我的面试题系列能对你的有所帮助!共勉! 愿你在未来的日子,保持热爱,奔赴山海! 每日三道面试题,成就更好自我昨天既然你有讲到字符串常量池是吧,那这样吧 1 ...
每日三道面试题，通往自由的道路10——JMM篇
茫茫人海千千万万,感谢这一秒你看到这里.希望我的面试题系列能对你的有所帮助!共勉! 愿你在未来的日子,保持热爱,奔赴山海! 每日三道面试题,成就更好自我今天我们还是继续聊聊多线程的一些其他话题吧! ...
每日三道面试题，通往自由的道路13——锁+Volatile
茫茫人海千千万万,感谢这一秒你看到这里.希望我的面试题系列能对你的有所帮助!共勉! 愿你在未来的日子,保持热爱,奔赴山海! 每日三道面试题,成就更好自我我们既然聊到了并发多线程的问题,怎么能少得了锁 ...

随机推荐

关于Parallel.For/Foreach并行方法中的localInit, body, localFinally使用
对集合成员的操作往往可以通过并行来提高效率,.NET Parallel类提供了简单的方法来帮助我们实现这种并行,比如Paralle.For/ForEach/Invoke方法. 其中,For/ForEa ...
Flash Media Server 4.5 序列号（fms4.5 激活码）
激活码一枚 ,网上找不到的..我今天放出来了哦... 1462-5864-7783-6034-8316-3718 (亲测可用) 安装前找到系统盘下windows/system32/driv ...
通过RFC给SAP新建用户
1.首先引用dll,然后在程序开头:using SAP.Middleware.Connector; 2.接下去就是设置登陆参数了,以前相关博文都有说明: public class MyBackendC ...
js判定IE
var ie=!-[1,]; 这句话对于多数前端来说都很熟悉,遇到判定是否是ie浏览器就用这个,但是对于由来以及为什么可能没有深入了解过. 短短6个bytes就做了判定.这个表达式是利用IE和标准浏览 ...
Python Django开发 1
先配置个虚拟环境,在Flask第一篇文章有写,这里就跳过了比如我的Django的目录是:C:\Workspaces\DjangoDemo,已经安装好了名为venv虚拟目录,接下来安装django框架 ...
【软件分析与挖掘】A Comparative Study of Supervised Learning Algorithms for Re-opened Bug Prediction
摘要: 本文主要是评估多种监督机器学习算法的有效性,这些算法用于判断一个错误报告是否是reopened的,算法如下: 7种监督学习算法:kNN,SVM, SimpleLogistic,Bayesian ...
12306外包给阿里巴巴/IBM到底是否可行？
春运开始以后 12306 免不了要罢工几次,毕竟人民群众买票回家的热情实在是高涨,12306 很难承受如此大的压力.每次 12306 网站罢工以后都会有人忍不住对其进行吐槽,而还有人认为如果把 123 ...
Rpath handling on Linux
The solution in the article below seems promising: http://www.blaenkdenum.com/notes/cmake/#rpath set ...
shell 和awk性能对比
time for ((i=0;i<10000;i++)) do ((sum+=i)); done real 0m0.086suser 0m0.079ssys 0m0.007s ...
DDD：《实现领域驱动》拾贝（待续）
Design is not just what it looks like and feels like. Design is how it works.

每日微软面试题——day 6（打印所有对称子串）

每日微软面试题——day 6（打印所有对称子串）

每日微软面试题——day 6（打印所有对称子串）的更多相关文章

随机推荐

热门专题