func_code_string: #include <bits/stdc++.h>   #define ll long long   #define db long double   #define x first   #define y second   #define mp make_pair   #define pb push_back   #define all(a) a.begin(), a.end()      using namespace std;      const int MAGIC = 300;   const int BLOCKS = 160000/MAGIC;      vector<int> tree;   vector<int> leave_block;      int add[BLOCKS];   int cnt[BLOCKS];      int n;      void recalc(int block) {     for (int i = block * MAGIC; i < min(n, (block + 1) * MAGIC); ++i) {       tree[i] = max(0, tree[i] - add[block]);     }     add[block] = 0;        for (int i = block * MAGIC; i < min(n, (block + 1) * MAGIC); ++i) {       int W = tree[i];       if (W < block * MAGIC) leave_block[i] = W;       else leave_block[i] = leave_block[W];     }      }      int layer(int x) {     return x/MAGIC;   }      int go_outer(int x) {     return max(0, leave_block[x] - add[layer(x)]);   }      int go(int x) {     return max(0, tree[x] - add[layer(x)]);   }      int main(){   #ifdef LOCAL    freopen( H_input.txt ,  r , stdin);    //freopen( H_output.txt ,  w , stdout);   #endif    ios_base::sync_with_stdio(0);    cin.tie(0);        int q;     cin >> n >> q;        tree.assign(n, 0);     for (int i = 1; i < n; ++i) {       cin >> tree[i];       tree[i]--;     }        leave_block.assign(n, 0);        for (int i = 0; i * MAGIC < n; ++i) {       recalc(i);     }        for (int i = 0; i < q; ++i) {       int tp;       cin >> tp;          //cout <<   ===   << go_outer(4) << endl;          if (tp == 1) {         int l, r, x;         cin >> l >> r >> x;         l--, r--;         for (int j = 0; j * MAGIC < n; ++j) {           int L = j*MAGIC, R = min(n, (j+1)*MAGIC) - 1;                      int pl = max(L, l), pr = min(R, r);           if (pl > pr) continue;           if (pl != L || pr != R || cnt[j] <= MAGIC) {             if (pl == L && pr == R) {               cnt[j]++;               add[j]+=x;               add[j] = min(add[j], (int) 1e8);             }             else {               for (int e = pl; e <= pr; ++e) tree[e] = max(0, tree[e] - x);             }           //cout <<   ???   << j << endl;             recalc(j);             //cout << leave_block[3] <<     << tree[3] <<     << pl <<      << pr  << endl;           }            else {             add[j]+=x;             add[j] = min(add[j], (int) 1e8);           }            }       }          else {         int u, v;         cin >> u >> v;            u--, v--;         while (true) {           if (u == v) break;           //cout << u <<     << v << endl;           //cout << go_outer(u) <<     << go_outer(v) << endl;           if (layer(u) < layer(v)) {             swap(u, v);           }           if (layer(u) > layer(v)) {             u = go_outer(u);           }           else {             int A = go_outer(u), B = go_outer(v);             if (A!=B) {               u = A, v = B;             }             else {               while (u != v) {                 if (u > v) u = go(u);                 else v = go(v);                }             }           }         }            cout << u+1 <<   n ;             }     }         }   