Finding Palindromes - 猥琐的字符串（Manacher+trie）

#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;

const int MAXN = 2e6+7;
const int oo = 1e9+7;

struct Trie
{///字典树的节点
    int next[26];
    int leaf;///以这个节点为终点的叶子节点个数
    int count;///后面回文串的数量

    void Free()
    {
        leaf = count = 0;
        memset(next, false, sizeof(next));
    }

}trie[MAXN];

int top;///配合字典树使用，top表示没有使用的内存
int start[MAXN], p[MAXN<<1];
char MumStr[MAXN], Estr[MAXN<<1];
bool suffix[MAXN];///后缀是否是回文串
bool prefix[MAXN];///前缀是否是回文串

void BuildTrie(int n)
{
    int p = 0;

    for(int i=start[n+1]-1; i>=start[n]; i--)
    {///把字符串倒插进去
        int k = MumStr[i] - ‘a‘;

        trie[p].count += prefix[i];

        if(trie[p].next[k] == 0)
        {
            trie[p].next[k] = ++top;
            trie[top].Free();
        }
        p = trie[p].next[k];
    }

    trie[p].leaf += 1;
}
void Manacher(int n)
{
    int i, id=0, len=1;

    Estr[0] = ‘$‘;

    for(i=start[n]; i<start[n+1]; i++)
    {
        Estr[len++] = ‘#‘;
        Estr[len++] = MumStr[i];

        suffix[i] = false;
        prefix[i] = false;
    }
    Estr[len] = ‘#‘;
    Estr[len+1] = 0;

    for(i=2; i<len; i++)
    {
        p[i] = 1;

        if(p[id]+id > i)
            p[i] = min(p[id*2-i], p[id]+id-i);

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

        if(p[id]+id < p[i]+i)
            id = i;

        if(p[i] == i)
            prefix[ start[n]+p[i]-2 ] = true;
        if(p[i]+i-1 == len)
            suffix[ start[n+1]-p[i]+1 ] = true;
    }
}
int Query(int n)
{
    int i, p=0, sum = 0;

    for(i=start[n]; i<start[n+1]; i++)
    {
        int k = MumStr[i] - ‘a‘;

        if(trie[p].next[k] == 0)
            break;

        p = trie[p].next[k];

        if(suffix[i+1] || i==start[n+1]-1)
            sum += trie[p].leaf;
    }

    if(i == start[n+1])
        sum += trie[p].count;

    return sum;
}

int main()
{
    int N;

    while(scanf("%d", &N) != EOF)
    {
        int i, len;

        top = 0;
        trie[0].Free();

        for(i=1; i<=N; i++)
        {
            scanf("%d%s", &len, MumStr+start[i]);
            start[i+1] = start[i] + len;

            Manacher(i);
            BuildTrie(i);
        }

        long long ans = 0;

        for(i=1; i<=N; i++)
            ans += Query(i);

        printf("%lld\n", ans);
    }

    return 0;
}
/**
2
3 abc
4 acba

*/