func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 5e5 + 5;   int n;   char s[N];   struct SuffixAutomaton {     struct node {       int ch[26], par;       int len;     } t[N << 1];     int root, tail, cnt;     inline int newnode(int len) {       t[++cnt].len = len;       return cnt;     }     inline void init() { root = tail = newnode(0); }     inline int extend(int c) {       int p = tail, np = newnode(t[tail].len + 1);       for (; p && !t[p].ch[c]; p = t[p].par) t[p].ch[c] = np;       if (!p)         t[np].par = root;       else if (t[t[p].ch[c]].len == t[p].len + 1)         t[np].par = t[p].ch[c];       else {         int q = t[p].ch[c], nq = newnode(t[p].len + 1);         memcpy(t[nq].ch, t[q].ch, sizeof(t[nq].ch));         t[nq].par = t[q].par;         t[np].par = t[q].par = nq;         for (; p && t[p].ch[c] == q; p = t[p].par) t[p].ch[c] = nq;       }       return tail = np;     }   } SAM;   int id[N];   namespace tree {   int hed[N << 1], to[N << 1], nxt[N << 1], fa[N << 1], cnt, anc[N << 1][20];   int fromlen[N << 1];   inline void adde(int u, int v) {     ++cnt;     to[cnt] = v, nxt[cnt] = hed[u];     hed[u] = cnt;   }   vector<pair<int, int> > tags[N << 1];   inline void dfs(int x, int pre) {     fa[x] = pre;     anc[x][0] = fa[x];     fromlen[x] = SAM.t[SAM.t[x].par].len + 1;     if (x == 1) fromlen[x] = 0;     for (int i = 1; i < 20; i++) anc[x][i] = anc[anc[x][i - 1]][i - 1];     for (int i = hed[x]; i; i = nxt[i]) {       int v = to[i];       dfs(v, x);     }   }   inline void pushtag(int x, int id, int f) {     int pos = x;     for (int i = 19; ~i; i--) {       if (SAM.t[anc[pos][i]].len > f) pos = anc[pos][i];     }     while (tags[pos].size() == 0 || tags[pos].back().first <= f) {       if (tags[pos].size() != 0 && tags[pos].back().first == SAM.t[pos].len)         break;       tags[pos].push_back(pair<int, int>(min(SAM.t[pos].len, f), id));       pos = fa[pos];     }   }   inline int find(int x, int id) {     int pos = x;     for (int i = 19; ~i; i--) {       int nxtpos = anc[pos][i];       if (!nxtpos) continue;       if (tags[nxtpos].size() == 0)         pos = nxtpos;       else {         if (fromlen[nxtpos] + tags[nxtpos][0].second > id) {           pos = nxtpos;         }       }     }     pos = fa[pos];     if (!pos) return 0;     int l = 0, r = (int)tags[pos].size() - 1;     while (l < r) {       int mid = (l + r + 1) >> 1;       int stlen = (mid == 0 ? fromlen[pos] : tags[pos][mid - 1].first + 1);       if (stlen + tags[pos][mid].second <= id)         l = mid;       else         r = mid - 1;     }     int finalend = min(tags[pos][l].first, id - tags[pos][l].second);     return finalend;   }   }  // namespace tree   int f[N];   int main() {     SAM.init();     cin >> n;     scanf( %s , s + 1);     reverse(s + 1, s + n + 1);     for (int i = 1; i <= n; ++i) id[i] = SAM.extend(s[i] -  a );     for (int i = 1; i <= SAM.cnt; i++)       if (SAM.t[i].par) tree::adde(SAM.t[i].par, i);     tree::dfs(1, 0);     int ans = 0;     for (int i = 1; i <= n; i++) {       f[i] = max(f[i], tree::find(id[i], i - 1) + 1);       if (i < n) f[i + 1] = max(f[i + 1], tree::find(id[i], i) + 1);       ans = max(ans, f[i]);       tree::pushtag(id[i], i, f[i]);     }     cout << ans << endl;   }   