T了什么鬼

#include <bits/stdc++.h>

inline int RPgetINF(void) {
    int f = 1, x = 0; char ch;
    do {ch = getchar(); if (ch == '-') f = -1;} while (ch < '0' || ch > '9');
    do {x = x * 10 + ch - '0'; ch = getchar();} while (ch >= '0' && ch <= '9');
    return x * f;
}

std::string str, s2;
int lty[11000010 * 2];

int main() {
    str = "%#";
    std::cin >> s2;
    int len = s2.length();
    for (int i = 0; i < len; i++) {
        str = str + s2[i];
        str = str + '#';
    }
    int n = str.length();
    int maxRight = 0, mid = 0, ans = 0;
    for (int i = 1; i < n; i++) {
        if (i < maxRight) lty[i] = std::min(lty[2 * mid - i], maxRight - i);
        else lty[i] = 1;
        while (str[lty[i] + i] == str[i - lty[i]]) lty[i]++;
        if (lty[i] + i > maxRight) {
            mid = i;
            maxRight = lty[i] + i;
        }
        ans = std::max(ans, lty[i]);
    }
    printf("%d\n", ans - 1);
    return 0;
}