Manacher

string Manacher(string s) {
    // Insert '#'
    string t = "$#";
    for (int i = 0; i < s.size(); ++i) {
        t += s[i];
        t += "#";
    }
    // Process t
    vector<int> p(t.size(), 0);
    int mx = 0, id = 0, resLen = 0, resCenter = 0;
    for (int i = 1; i < t.size(); ++i) {
        p[i] = mx > i ? min(p[2 * id - i], mx - i) : 1;
        while (t[i + p[i]] == t[i - p[i]]) ++p[i];
        if (mx < i + p[i]) {
            mx = i + p[i];
            id = i;
        }
        if (resLen < p[i]) {
            resLen = p[i];
            resCenter = i;
        }
    }
    return s.substr((resCenter - resLen) / 2, resLen - 1);
}

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版权声明：本文为CSDN博主「dby_freedom」的原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/Dby_freedom/java/article/details/93191052