https://www.luogu.org/problem/show?pid=2799
判断整个字符串是否对称,如果对称,那么从中间分开继续比较。
注意,当当前总长度为奇数时,直接退出,因为镜子不会把项链变为奇数长
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define ms(i,j) memset(i, j, sizeof i);
int n;
char ch[100005];
int dfs(int r)
{
if (r%2==1) return r;
int mid = r/2;
for (int i=1;i<=mid;i++)
{
if (ch[i]!=ch[r-i+1]) return r;
}
return dfs(mid);
}
int main()
{
scanf("%s", ch+1);
n = strlen(ch+1);
printf("%d\n", dfs(n));
system("pause");
return 0;
}