hdu3068 manacher算法模板

/**********************jibancanyang************************** *Author        :jibancanyang *Created Time  : 三  4/27 09:43:05 2016 *File Name     : jy.cpp *Problem: *Get:***********************[e-mail]**********************/#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#include <vector>#include <queue>#include <set>#include <map>#include <string>#include <cmath>#include <cstdlib>#include <ctime>#include <stack>using namespace std;typedef pair<int, int> pii;typedef long long ll;typedef unsigned long long ull;vector<int> vi;#define pr(x) cout << #x << ": " << x << "  " #define pl(x) cout << #x << ": " << x << endl;#define xx first#define yy second#define sa(n) scanf("%d", &(n))#define sal(n) scanf("%lld", &(n))#define sai(n) scanf("%I64d", &(n))#define rep(i, a, n) for (int i = a; i < n; i++)#define vep(c) for(decltype((c).begin() ) it = (c).begin(); it != (c).end(); it++) const int mod = int(1e9) + 7, INF = 0x3fffffff, maxn = 1e5 + 1e4 + 12;char s[maxn * 2], T[maxn * 2];int ti, P[maxn * 2];// 将S转换成T // 比如，S = "abba", T = "^#a#b#b#a#$"// ^和$符号用来表示开始和结束，并且避免边界检查。void preProcess(){    int n = strlen(s);    ti = 0;    if (n == 0) {T[0] = '^', T[1] = '$'; return;}    T[ti++] = '^';    for (int i = 0; i < n; i++)        T[ti++] = '#', T[ti++] = s[i];    T[ti++] = '#', T[ti++] = '$';}int  manacher(){    preProcess();    int n = ti;    int C = 0, R = 0;    for (int i = 1; i < n - 1; i++) {        int i_mirror = 2 * C - i; // 等于i' = C - (i-C)    P[i] = (R > i) ? min(R-i, P[i_mirror]) : 0;    // 尝试扩展中心为i的回文    while (T[i + 1 + P[i]] == T[i - 1 - P[i]])        P[i]++;    // 如果中心为i的回文超越了R，根据已扩展的回文来调整中心    if (i + P[i] > R) {        C = i;        R = i + P[i];        }    }    // 找出P中的最大值    int maxLen = 0;    int centerIndex = 0;    for (int i = 1; i < n-1; i++) {        if (P[i] > maxLen) {            maxLen = P[i];            centerIndex = i;        }    }    //最长回文子串的起点    int stp = (centerIndex - 1 - maxLen) / 2;    //返回最长回文子串,其长度为maxLen    return maxLen;}int main(void){#ifdef LOCAL    //freopen("/Users/zhaoyang/in.txt", "r", stdin);    //freopen("/Users/zhaoyang/out.txt", "w", stdout);#endif    ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);    while (~scanf("%s", s)){        printf("%d\n", manacher());    }    return 0;}