（回文串 Manacher ）Girls' research -- hdu -- 3294

#include<iostream>
#include<stdio.h>
#include<string.h>
#include<algorithm>

using namespace std;
#define INF 0x3f3f3f3f
#define N 1000007

char s[N], S[N], str[N];
int  p[N], Mid;

int Manacher()
{
    int MaxLen = 0, index = 0, ans = 1;
    int len = strlen(s);
    Mid = 0;

    for(int i=2; i<len; i++)
    {
        if(MaxLen>i) p[i] = min(p[index*2-i], MaxLen-i);
        else p[i] = 1;

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

        if(p[i]+i>MaxLen)
        {
            MaxLen = p[i] + i;
            index = i;
        }

        if(p[i]>ans)
        {
            ans = p[i];
            Mid = i;
        }
    }
    return ans-1;
}

int main()
{
    char ch[10];

    while(scanf("%s%s", ch, S)!=EOF)
    {
        int i, len = strlen(S), number;
        char c;

        number = ch[0]-‘a‘;

        s[0] = ‘$‘;
        for(i=0; i<len; i++)
        {
            c = S[i] - number;
            if(c<‘a‘)
                c += 26;
            S[i] = c;

            s[i*2+1] = ‘#‘;
            s[i*2+2] = S[i];
        }
        s[i*2+1] = ‘#‘;
        s[i*2+2] = 0;

        int ans = Manacher();

        if(ans<2)
           printf("No solution!\n");
        else
        {
            int L = Mid/2-(ans+1)/2;
            printf("%d %d\n", L, L+ans-1);
            memset(str, 0, sizeof(str));
            strncpy(str, S+L, ans);
            printf("%s\n", str);
        }
    }
    return 0;
}