性感代码求条

#include<bits/stdc++.h>
#define IOS ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
using namespace std;
const int maxn=1.1e7+5;
int n,p[maxn],mid,r,ans;
string s="$#",str;
int main(){
    cin>>str;
    char ch;
    for(int i=0;i<str.size();i++){
        ch=str[i];
        s=s+ch+'#';
    }
    s+='@';
    // cout<<s<<"\n";
    n=s.size();
    s=' '+s;
    for(int i=1;i<=n;i++){
        if(i<=r)p[i]=min(p[mid*2-i],r-i+1);
        while(i-p[i]>=1&&i+p[i]<=n&&s[i-p[i]]==s[i+p[i]])p[i]++;
        if(i+p[i]>r)r=i+p[i]-1,mid=i;
        if(p[i]>ans)ans=p[i];
    }
    cout<<(ans-1);
}