【题目链接】:http://hihocoder.com/problemset/problem/1032

【题意】

【题解】



原文地址:https://segmentfault.com/a/1190000003914228

UPD1

RL[j]的定义是,回文最左或最右端到中心点j的距离



【Number Of WA】



0



【完整代码】

#include <bits/stdc++.h>

using namespace std;

#define lson l,m,rt<<1

#define rson m+1,r,rt<<1|1

#define LL long long

#define rep1(i,a,b) for (int i = a;i <= b;i++)

#define rep2(i,a,b) for (int i = a;i >= b;i--)

#define mp make_pair

#define pb push_back

#define fi first

#define se second

#define ms(x,y) memset(x,y,sizeof x)

typedef pair<int,int> pii;

typedef pair<LL,LL> pll;

const int dx[9] = {0,1,-1,0,0,-1,-1,1,1};

const int dy[9] = {0,0,0,-1,1,-1,1,-1,1};

const double pi = acos(-1.0);

const int N = 2e6+100;

int t,rad[N];

char str[N],s[N];

int main()

{

    //freopen("F:\\rush.txt","r",stdin);

    ios::sync_with_stdio(false),cin.tie(0);//scanf,puts,printf not use

    cin >> t;

    while (t--)

    {

        cin >> str;

        int n = 1;

        s[0] = '$',s[1] = '#';

        for (int i = 0;str[i];i++)

        {

            s[++n] = str[i];

            s[++n] = '#';

        }

        int maxright = 0,pos=0;

        rep1(i,1,n)

        {

            if (maxright>i)

                rad[i] = min(maxright-i,rad[pos*2-i]);

            else

                rad[i] = 1;

            while (s[i-rad[i]]==s[i+rad[i]]) rad[i]++;

            if (i+rad[i]-1>maxright)

            {

                maxright = i+rad[i]-1;

                pos = i;

            }

        }

        int ans = rad[1]-1;

        rep1(i,2,n)

            ans = max(ans,rad[i]-1);

        cout << ans << endl;

    }

    return 0;

}