func_code_string: #include <bits/stdc++.h>   using namespace std;   const int LG = 18;   const int MX_N = 100005;   int n, q;   struct LowestCommonAncestor {     int clk, par[MX_N][LG];     int st[MX_N], h[MX_N];     vector<int> G[MX_N];     void addEdge(int u, int v) {       G[u].push_back(v);       G[v].push_back(u);     }     void dfs(int u = 1, int p = 0) {       st[u] = ++clk;       par[u][0] = p;       h[u] = h[p] + 1;       for (int i = 1; i < LG; i++) par[u][i] = par[par[u][i - 1]][i - 1];       for (auto& v : G[u])         if (v != p) dfs(v, u);     }     int LCA(int u, int v) {       if (h[u] < h[v]) swap(u, v);       for (int i = LG - 1; i >= 0; i--)         if (h[par[u][i]] >= h[v]) u = par[u][i];       if (u == v) return u;       for (int i = LG - 1; i >= 0; i--)         if (par[u][i] != par[v][i]) u = par[u][i], v = par[v][i];       return par[u][0];     }   };   struct SegTree {     pair<int, int> seg1[MX_N * 4], seg2[MX_N * 4];     void Merge(int nd, int lft, int rgt) {       seg1[nd] = min(seg1[lft], seg1[rgt]);       seg2[nd] = max(seg2[lft], seg2[rgt]);     }     void Bld(int* a, int nd = 1, int l = 1, int r = n) {       if (l == r) {         seg1[nd] = seg2[nd] = {a[l], l};         return;       }       int mid = l + (r - l) / 2, lft = nd << 1, rgt = lft | 1;       Bld(a, lft, l, mid);       Bld(a, rgt, mid + 1, r);       Merge(nd, lft, rgt);     }     pair<int, int> QryMN(int L, int R, int nd = 1, int l = 1, int r = n) {       if (l > R or r < L) return {INT_MAX, INT_MAX};       if (l >= L and r <= R) return seg1[nd];       int mid = l + (r - l) / 2, lft = nd << 1, rgt = lft | 1;       return min(QryMN(L, R, lft, l, mid), QryMN(L, R, rgt, mid + 1, r));     }     pair<int, int> QryMX(int L, int R, int nd = 1, int l = 1, int r = n) {       if (l > R or r < L) return {INT_MIN, INT_MIN};       if (l >= L and r <= R) return seg2[nd];       int mid = l + (r - l) / 2, lft = nd << 1, rgt = lft | 1;       return max(QryMX(L, R, lft, l, mid), QryMX(L, R, rgt, mid + 1, r));     }   };   SegTree sg;   LowestCommonAncestor olca;   void calc(int lca, int bd, int& res, int& bad) {     if (res < olca.h[lca]) res = olca.h[lca], bad = bd;   }   void solution(int l, int r, int& res, int& bad) {     pair<int, int> mnD = sg.QryMN(l, r);     pair<int, int> mxD = sg.QryMX(l, r);     int L = mnD.second;     int R = mxD.second;     pair<int, int> tmp;     if (L == l) {       tmp = sg.QryMN(l + 1, r);       calc(olca.LCA(tmp.second, R), L, res, bad);     } else if (L == r) {       tmp = sg.QryMN(l, r - 1);       calc(olca.LCA(tmp.second, R), L, res, bad);     } else {       tmp = min(sg.QryMN(l, L - 1), sg.QryMN(L + 1, r));       calc(olca.LCA(tmp.second, R), L, res, bad);     }     if (R == l) {       tmp = sg.QryMX(l + 1, r);       calc(olca.LCA(tmp.second, L), R, res, bad);     } else if (R == r) {       tmp = sg.QryMX(l, r - 1);       calc(olca.LCA(tmp.second, L), R, res, bad);     } else {       tmp = max(sg.QryMX(l, R - 1), sg.QryMX(R + 1, r));       calc(olca.LCA(tmp.second, L), R, res, bad);     }   }   int main() {     scanf( %d %d , &n, &q);     for (int i = 2, p; i <= n; i++) {       scanf( %d , &p);       olca.addEdge(p, i);     }     olca.dfs();     sg.Bld(olca.st);     while (q--) {       int l, r;       scanf( %d %d , &l, &r);       if (r - l == 1) {         int hh = max(olca.h[l], olca.h[r]);         int nn = (hh == olca.h[l]) ? r : l;         printf( %d %d n , nn, hh - 1);         continue;       }       int res = 0, bad = 0;       solution(l, r, res, bad);       printf( %d %d n , bad, res - 1);     }     return 0;   }   