双指针还是比较简单的 #include<bits/stdc++.h>

using namespace std;

int main()

{

string s;

cin>>s;

int l=0,r=s.length()-2;

while(l<r)

{

	if(s[l++]==s[r--])

	continue;

	else

	{

		cout<<"No";

	    return 0;

	}

}

cout<<"Yes";

return 0;

}