完美可逆弦
给你一个字符串“str”，任务是检查“str”的所有可能的子字符串的反转是否出现在“str”中。
示例:
Input : str = "ab"
Output: "NO"
// all substrings are "a","b","ab" but reverse
// of "ab" is not present in str
Input : str = "aba"
Output: "YES"
Input : str = "abab"
Output: "NO"
// All substrings are "a", "b", "a", "b", "ab",
// "ba", "ab", "aba", "bab", "abab" but reverse of
// "abab" is not present in str
这个问题的一个简单解决方案是生成所有可能的‘ST’子串，并检查它们的反向是否线性存在于‘str’中。 这个问题的有效解决方案是基于这样一个事实，即当且仅当整个字符串“str”是回文时，“str”的所有子字符串的反向将存在于“str”中。我们可以通过考虑整个字符串来证明这个事实，只有当它是回文时，它的反义词才会存在。如果一个字符串是回文，那么所有子字符串的所有反转都存在。
下面是上述想法的实现。
C++
// C++ program to check if a string is perfect
// reversible or nor
#include<bits/stdc++.h>
using namespace std;
// This function basically checks if string is
// palindrome or not
bool isReversible(string str)
{
int i = 0, j = str.length()-1;
// iterate from left and right
while (i < j)
{
if (str[i] != str[j])
return false;
i++;
j--;
}
return true;
}
// Driver program to run the case
int main()
{
string str="aba";
if (isReversible(str))
cout << "YES";
else
cout << "NO";
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to check
// if a string is perfect
// reversible or nor
import java.io.*;
class GFG
{
// This function basically
// checks if string is
// palindrome or not
static boolean isReversible(String str)
{
int i = 0, j = str.length() - 1;
// iterate from
// left and right
while (i < j)
{
if (str.charAt(i) != str.charAt(j))
return false;
i++;
j--;
}
return true;
}
// Driver Code
public static void main (String[] args)
{
String str = "aba";
if (isReversible(str))
System.out.print("YES");
else
System.out.print( "NO");
}
}
// This code is contributed
// by anuj_67.
Python 3
# Python3 program to check if
# a string is perfect reversible or not
# This function basically checks
# if string is palindrome or not
def isReversible(str):
i = 0; j = len(str) - 1;
# iterate from left and right
while (i < j):
if (str[i] != str[j]):
return False;
i += 1;
j -= 1;
return True;
# Driver Code
str = "aba";
if (isReversible(str)):
print("YES");
else:
print("NO");
# This code is contributed by Princi Singh
C#
// C# program to check if a string
// is perfect reversible or nor
using System;
class GFG
{
// This function basically checks if
// string is palindrome or not
public static bool isReversible(string str)
{
int i = 0, j = str.Length - 1;
// iterate from left and right
while (i < j)
{
if (str[i] != str[j])
{
return false;
}
i++;
j--;
}
return true;
}
// Driver Code
public static void Main(string[] args)
{
string str = "aba";
if (isReversible(str))
{
Console.Write("YES");
}
else
{
Console.Write("NO");
}
}
}
// This code is contributed
// by anuj_67
java 描述语言
<script>
// JavaScript program to check if a
// string is perfect reversible or not
// This function basically checks
// if string is palindrome or not
function isReversible(str)
{
var i = 0,
j = str.length - 1;
// Iterate from left and right
while (i < j)
{
if (str[i] != str[j])
return false;
i++;
j--;
}
return true;
}
// Driver Code
var str = "aba";
if (isReversible(str))
document.write("YES");
else
document.write("NO");
// This code is contributed by rdtank
</script>
*输出:*
YES
本文由 沙莎克·米什拉(古卢) 供稿。如果你喜欢 GeeksforGeeks 并想投稿，你也可以使用contribute.geeksforgeeks.org写一篇文章或者把你的文章邮寄到 contribute@geeksforgeeks.org。看到你的文章出现在极客博客主页上，帮助其他极客。 如果发现有不正确的地方，或者想分享更多关于上述话题的信息，请写评论。
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