func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxn = 5e5 + 5, mod = 1e9 + 7, lg = 22;   int n, suf[maxn], lcp[maxn], Rank[lg][maxn], pw2[30], rmq[lg][maxn], lst,       seg[maxn * 4], klg[maxn], dp[maxn];   string s;   vector<pair<pair<int, int>, int>> V2;   void raDix_Sort() {     vector<vector<pair<pair<int, int>, int>>> V1(maxn), V3(maxn);     for (auto i : V2) V1[i.first.second + 1].push_back(i);     V2.clear();     for (int i = 0; i <= n; i++)       for (auto j : V1[i]) V3[j.first.first].push_back(j);     for (int i = 0; i < n; i++)       for (auto j : V3[i]) V2.push_back(j);   }   void build_suffix_array() {     vector<pair<int, int>> V;     V2.resize(n);     for (int i = 0; i < n; i++) V.push_back({s[i] -  a , i});     sort(V.begin(), V.end());     for (int i = 1; i < n; i++)       Rank[0][V[i].second] =           Rank[0][V[i - 1].second] + ((V[i].first) != (V[i - 1].first));     for (int i = 0; pw2[i] < n; i++) {       for (int j = 0; j < n; j++) {         int x = -1;         if (j + pw2[i] < n) x = Rank[i][j + pw2[i]];         V2[j] = {{Rank[i][j], x}, j};       }       raDix_Sort();       Rank[i + 1][V2[0].second] = 0;       for (int j = 1; j < n; j++)         Rank[i + 1][V2[j].second] =             Rank[i + 1][V2[j - 1].second] + ((V2[j].first) != (V2[j - 1].first));       lst = i + 1;       if (Rank[i + 1][V2[n - 1].second] == n - 1) break;     }     for (int i = 0; i < n; i++) suf[Rank[lst][i]] = i;     for (int i = 0; i < n - 1; i++) {       int p1 = suf[i], p2 = suf[i + 1];       for (int j = lst; j >= 0; j--) {         if (Rank[j][p1] != Rank[j][p2]) continue;         if (p1 >= n || p2 >= n) continue;         p1 += pw2[j];         p2 += pw2[j];       }       lcp[i] = p1 - suf[i];       rmq[0][i] = lcp[i];     }     n--;     for (int j = 1; j <= klg[n]; j++) {       for (int i = 0; i <= n - pw2[j]; i++)         rmq[j][i] = min(rmq[j - 1][i], rmq[j - 1][i + pw2[j - 1]]);     }     n++;   }   void fix(int p, int x, int v = 1, int s = 0, int e = n) {     if (e - s == 1) {       seg[v] = x;       return;     }     int mid = (e + s) >> 1, lc = v << 1, rc = lc | 1;     if (mid > p)       fix(p, x, lc, s, mid);     else       fix(p, x, rc, mid, e);     seg[v] = max(seg[lc], seg[rc]);   }   int get(int l, int r, int v = 1, int s = 0, int e = n) {     if ((l >= e) || (r <= s)) return 0;     if ((l <= s) && (e <= r)) return seg[v];     int mid = (e + s) >> 1, lc = v << 1, rc = lc | 1;     return max(get(l, r, lc, s, mid), get(l, r, rc, mid, e));   }   int get_mn(int l, int r) {     return min(rmq[klg[r - l]][l], rmq[klg[r - l]][r - pw2[klg[r - l]]]);   }   bool check(int l, int r) {     int len = r - l, p = Rank[lst][l], p1, p2, l1 = p, r1 = n;     while (l1 != r1 - 1) {       int mid = (l1 + r1) >> 1;       if (get_mn(l1, mid) >= len)         l1 = mid;       else         r1 = mid;     }     p2 = r1;     l1 = -1;     r1 = p;     while (l1 != r1 - 1) {       int mid = (l1 + r1) >> 1;       if (get_mn(mid, r1) >= len)         r1 = mid;       else         l1 = mid;     }     p1 = r1;     if (get(p1, p2) >= len)       return 1;     else       return 0;   }   int main() {     ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);     pw2[0] = 1;     klg[1] = 0;     for (int i = 1; i < 25; i++) pw2[i] = (pw2[i - 1] * 2);     for (int i = 2; i < maxn; i++)       klg[i] = klg[i - 1] + (pw2[klg[i - 1]] * 2 == i);     cin >> n >> s;     build_suffix_array();     int ans = 1, l = n - 2, r = n - 1;     dp[n - 1] = 1;     fix(Rank[lst][n - 1], 1);     while (l >= 0) {       if (l == r - 1) {         dp[l] = 1;         l--;         continue;       }       if (!check(l, r - 1)) {         if (!check(l + 1, r)) {           r--;           fix(Rank[lst][r], dp[r]);           continue;         }       }       ans = max(ans, r - l);       dp[l] = r - l;       l--;     }     cout << ans << endl;   }   