func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 200005;   int n, log2n, q, C[N], L[N], R[N], tot = 0, f[N][25], up[N], de2[N];   long long de[N];   struct node {     long long min, sign;   } a[N * 4];   pair<int, int> E[2 * N];   vector<pair<int, int> > e[N];   void add1(int x, int k) {     for (; x <= n; x += x & (-x)) de[x] += k;   }   long long ask1(int x) {     long long res = 0;     for (; x; x -= x & (-x)) res += de[x];     return res;   }   void build(int l, int r, int now) {     if (l == r) {       a[now].min = ask1(l) + up[C[l]];       return;     }     int mid = (l + r) >> 1;     build(l, mid, now << 1);     build(mid + 1, r, now << 1 | 1);     a[now].min = min(a[now << 1].min, a[now << 1 | 1].min);   }   void update(int l, int r, int now, int k) {     a[now].min += k;     a[now].sign += k;   }   void down(int l, int r, int now) {     int mid = (l + r) >> 1;     update(l, mid, now << 1, a[now].sign);     update(mid + 1, r, now << 1 | 1, a[now].sign);     a[now].sign = 0;   }   void add2(int l, int r, int now, int s, int t, int k) {     if (s <= l && r <= t) {       update(l, r, now, k);       return;     }     down(l, r, now);     int mid = (l + r) >> 1;     if (s <= mid) add2(l, mid, now << 1, s, t, k);     if (t > mid) add2(mid + 1, r, now << 1 | 1, s, t, k);     a[now].min = min(a[now << 1].min, a[now << 1 | 1].min);   }   long long ask2(int l, int r, int now, int s, int t) {     if (s <= l && r <= t) return a[now].min;     down(l, r, now);     int mid = (l + r) >> 1;     long long res = 0x3f3f3f3f3f3f3f3f;     if (s <= mid) res = min(ask2(l, mid, now << 1, s, t), res);     if (t > mid) res = min(ask2(mid + 1, r, now << 1 | 1, s, t), res);     return res;   }   void dfs1(int u, int fa) {     f[u][0] = fa;     C[++tot] = u;     L[u] = tot;     for (int i = 0; i < e[u].size(); i++) {       int v = e[u][i].first;       if (v == fa) continue;       dfs1(v, u);     }     R[u] = tot;   }   void dfs2(int u, int fa) {     for (int i = 0; i < e[u].size(); i++) {       int v = e[u][i].first, w = e[u][i].second;       if (v == fa) continue;       de2[v] = de2[u] + 1;       add1(L[v], w);       add1(R[v] + 1, -w);       dfs2(v, u);     }   }   bool on(int u, int v) {     swap(u, v);     long long k = de2[u] - de2[v];     if (k < 0) return false;     for (int i = 0; k; i++, k >>= 1)       if (k & 1) u = f[u][i];     return (u == v);   }   int main() {     std::ios::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     cin >> n >> q;     log2n = log2(n);     for (int i = 1; i <= 2 * n - 2; i++) {       int u, v, w;       cin >> u >> v >> w;       if (i < n)         E[i] = {w, v};       else         E[i] = {w, u}, up[u] = w;       if (i >= n) continue;       e[u].push_back({v, w});       e[v].push_back({u, w});     }     dfs1(1, 0);     dfs2(1, 0);     for (int j = 1; j <= log2n; j++)       for (int i = 1; i <= n; i++) f[i][j] = f[f[i][j - 1]][j - 1];     build(1, n, 1);     for (int i = 0; i < q; i++) {       int c, x, y;       cin >> c >> x >> y;       if (c == 1) {         if (x < n) {           add1(L[E[x].second], -E[x].first + y);           add1(R[E[x].second] + 1, E[x].first - y);           add2(1, n, 1, L[E[x].second], R[E[x].second], -E[x].first + y);         } else           add2(1, n, 1, L[E[x].second], L[E[x].second], -E[x].first + y);         E[x].first = y;       } else {         if (on(x, y))           cout << ask1(L[y]) - ask1(L[x]) << endl;         else           cout << ask2(1, n, 1, L[x], R[x]) - ask1(L[x]) + ask1(L[y]) << endl;       }     }     return 0;   }   