String Function Calculation

#include <bits/stdc++.h>

using namespace std;

vector<int> sa(string& s) {
    int t = 1, n = s.length();
    vector<int> SA(n), g(n + 1), tg(n + 1);
    for(int i = 0; i < n; i++) {
        SA[i] = i;
        g[i] = s[i] - 'a';
    }

    while(t <= n) {
        g[n] = -1;
        auto cmp = [&](int x, int y) {
            if(g[x] == g[y])
                return g[x + t] < g[y + t];
            return g[x] < g[y];
        };
        sort(begin(SA), end(SA), cmp);

        tg[SA[0]] = 0;
        for(int i = 1; i < n; i++) {
            tg[SA[i]] = tg[SA[i-1]] + cmp(SA[i-1], SA[i]);
        }

        g = tg;
        t<<=1;
    }

    return SA;
}

vector<int> lcp(string& s, vector<int>& SA) {
    int n = s.length(), len = 0;
    vector<int> LCP(n), rsa(n);
    for(int i = 0; i < n; i++)
        rsa[SA[i]] = i;
    for(int i = 0; i < n; i++) {
        int k = rsa[i];
        if(k) {
            int j = SA[k-1];
            while(s[i + len] == s[j + len]) ++len;
            LCP[k] = len;
            if(len) --len;
        }
    }
    return LCP;
}
int solve(string& s) {
    int res = 0, n = s.length();
    auto SA = sa(s), LCP = lcp(s, SA);
    vector<int> V(n, -1);
    for(int i = 0; i < n; i++) {
        int len = n - SA[i], j = i;
        while(j < n and V[j] < len) {
            V[j] = len;
            res = max(res, len * (j - i + 1));
            j++;
            len = min(len, j < n ? LCP[j] : 0);
        }
    }
    return res;
}
int main() {
    string s;
    cin>>s;
    cout<<solve(s);

}