func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 5e5 + 5;   int n, Q, x;   int fa[N], fv[N];   vector<int> c[N];   struct nod {     int i, l, r;   } b;   vector<nod> a[N];   int pl, pr;   long long px;   long long t[N * 4], lz[N * 4];   void down(int i) {     if (lz[i]) {       t[i + i] += lz[i];       lz[i + i] += lz[i];       t[i + i + 1] += lz[i];       lz[i + i + 1] += lz[i];       lz[i] = 0;     }   }   void add(int i, int x, int y) {     if (y < pl || x > pr) return;     if (x >= pl && y <= pr) {       t[i] += px;       lz[i] += px;       return;     }     int m = x + y >> 1;     down(i);     add(i + i, x, m);     add(i + i + 1, m + 1, y);     t[i] = min(t[i + i], t[i + i + 1]);   }   void ft(int i, int x, int y) {     if (y < pl || x > pr) return;     if (x >= pl && y <= pr) {       px = min(px, t[i]);       return;     }     int m = x + y >> 1;     down(i);     ft(i + i, x, m);     ft(i + i + 1, m + 1, y);   }   int p[N], q[N], tp;   long long s[N];   const long long M = 1e18;   void dg(int x) {     p[x] = ++tp;     for (int j = 0, B = c[x].size() - 1; j <= B; j++) {       int y = c[x][j];       s[y] = s[x] + fv[y], dg(y);     }     q[x] = tp;     if (p[x] == q[x]) {       pl = pr = p[x];       px = s[x] - M;       add(1, 1, n);     }   }   long long ans[N];   void dfs(int x) {     for (int j = 0, B = a[x].size() - 1; j <= B; j++) {       pl = a[x][j].l, pr = a[x][j].r;       px = 1e18;       ft(1, 1, n);       ans[a[x][j].i] = px;     }     for (int j = 0, B = c[x].size() - 1; j <= B; j++) {       int y = c[x][j];       px = -fv[y];       pl = p[y];       pr = q[y];       add(1, 1, n);       px = fv[y];       pl = 1;       pr = p[y] - 1;       add(1, 1, n);       pl = q[y] + 1;       pr = n;       add(1, 1, n);       dfs(y);       px = -fv[y];       pl = q[y] + 1;       pr = n;       add(1, 1, n);       pl = 1;       pr = p[y] - 1;       add(1, 1, n);       px = fv[y];       pl = p[y];       pr = q[y];       add(1, 1, n);     }   }   int main() {     scanf( %d %d , &n, &Q);     for (int i = 1, B = n * 4; i <= B; i++) t[i] = 1e18;     for (int i = 2, B = n; i <= B; i++) {       scanf( %d %d , &fa[i], &fv[i]);       c[fa[i]].push_back(i);     }     for (int i = 1, B = Q; i <= B; i++) {       scanf( %d , &x);       scanf( %d %d , &b.l, &b.r);       b.i = i;       a[x].push_back(b);     }     dg(1);     dfs(1);     for (int i = 1, B = Q; i <= B; i++) printf( %I64d n , ans[i]);   }   