Language: C++

#include <bits/stdc++.h>
using namespace std;

#define for_(i,a,b) for(int i=(a);i<(b);++i)
#define for_rev(i,a,b) for(int i=(a);i>=(b);--i)

typedef long long lint;
typedef pair< int, int > pii;

// Segment Tree with Lazy Evaluate
template< typename DATA >
class SegmentTreeLazy {
private:
	int size__;
	vector< DATA > data, lazy;
	
	inline int left_t(int k) {
		return (k << 1) + 1;
	}
	
	inline int right_t(int k) {
		return (k << 1) + 2;
	}
	
	inline int center(int l, int r) {
		return (l + r) >> 1;
	}
	
public:
	SegmentTreeLazy() {}
	
	SegmentTreeLazy(int n, DATA ini, DATA lini) {
		for (size__ = 1; size__ < n; size__ <<= 1);
		data.assign(2 * size__ - 1, ini);
		lazy.assign(2 * size__ - 1, lini);
	}
	
	DATA calc(DATA d1, DATA d2) {
		return d1 + d2;
	}
	
	void lazyCalc(int k, DATA val) {
		lazy[k] += val;
	}
	
	inline void lazyEval(int l, int r, int k) {
		data[k] += lazy[k] * (r - l);
		
		if (k < size__ - 1) {
			lazyCalc(left_t(k), lazy[k]);
			lazyCalc(right_t(k), lazy[k]);
		}
		
		lazy[k] = DATA(0);
	}
	
	inline void updateAt(int k) {
		data[k] = calc(data[left_t(k)], data[right_t(k)]);
	}
	
	void update(int a, int b, DATA x) {
		update(a, b, x, 0, 0, size__);
	}
	
	void update(int a, int b, DATA x, int k, int l, int r) {
		lazyEval(l, r, k);
		
		if (r <= a || b <= l) return;
		if (a <= l && r <= b) {
			lazyCalc(k, x);
			lazyEval(l, r, k);
			return;
		}
		
		update(a, b, x, left_t(k), l, center(l, r));
		update(a, b, x, right_t(k), center(l, r), r);
		updateAt(k);
	}
	
	DATA query(int a, int b) {
		return query(a, b, 0, 0, size__);
	}
	
	DATA query(int a, int b, int k, int l, int r) {
		lazyEval(l, r, k);
		
		if (r <= a || b <= l) return 0;
		if (a <= l && r <= b) return data[k];
		DATA res =  calc(query(a, b, left_t(k), l, center(l, r)),
						 query(a, b, right_t(k), center(l, r), r));
		
		updateAt(k);
		return res;
	}
	
	int size() {
		return size__;
	}
};

int N, Q;
vector< int > edges[150010];

int depth[150010], parent[150010][30],
	open[150010], close[150010],
	open_index[150010], close_index[150010];
	
SegmentTreeLazy< lint > add_stl, sub_stl;

void makeLCA() {
	memset(open, -1, sizeof(open));
	memset(close, -1, sizeof(close));
	memset(depth, 0, sizeof(depth));
	
	int cnt = 0;
	stack< pii > st; st.push(pii(0, -1));
	
	while (!st.empty()) {
		pii var = st.top(); st.pop();
		int v = var.first, p = var.second;
		
		if (p != -2) {
			parent[v][0] = p;
			depth[v] = (p < 0) ? 0 : depth[p] + 1;
		}
		
		if (open[v] < 0) {
			open[v] = open_index[v] = cnt++;
			
			st.push(pii(v, -2));
			for (int u : edges[v]) st.push(pii(u, v));
		} else {
			close[v] = close_index[v] = cnt++;
		}
	}
	
	sort(open_index, open_index + N);
	sort(close_index, close_index + N);
	
	for_(k,0,24) for_(v,0,N) {
		if (parent[v][k] < 0) parent[v][k + 1] = -1;
		else parent[v][k + 1] = parent[ parent[v][k] ][k];
	}
}

int getLCA(int a, int b) {
	if (depth[a] > depth[b]) swap(a, b);
	
	for_(k,0,25) if ((depth[b] - depth[a]) >> k & 1) b = parent[b][k];
	
	if (a == b) return a;
	
	for_rev(k,24,0) {
		if (parent[a][k] != parent[b][k]) {
			a = parent[a][k];
			b = parent[b][k];
		}
	}
	
	return parent[a][0];
}

int upper_index(int *ary, int n, int x) { return upper_bound(ary, ary + n, x) - ary; }
int lower_index(int *ary, int n, int x) { return lower_bound(ary, ary + n, x) - ary; }

int getCost(int v) {
	int o = open[v];
	int A = upper_index(open_index, N, o), S = upper_index(close_index, N, o);
	return add_stl.query(0, A) - sub_stl.query(0, S);
}

int main() {
	cin >> N >> Q;
	
	for_(i,0,N-1) {
		int a, b;
		scanf("%d %d", &a, &b);
		edges[a].push_back(b);
	}
	
	makeLCA();
	
	add_stl = SegmentTreeLazy< lint >(N, 0, 0);
	sub_stl = SegmentTreeLazy< lint >(N, 0, 0);
		
	for_(i,0,Q) {
		int q, a, b;
		scanf("%d %d %d", &q, &a, &b);
		
		if (q) {
			int o = open[a], c = close[a];
			int oL = upper_index(open_index, N, o), oR = lower_index(open_index, N, c);
			int cL = upper_index(close_index, N, o), cR = lower_index(close_index, N, c);
			
			add_stl.update(oL, oR, b);
			sub_stl.update(cL, cR, b);
		} else {
			int p = getLCA(a, b);
			cout << getCost(a) + getCost(b) - 2 * getCost(p) << endl;
		}
	}
}

Compiler output:
a.cc:105:35: error: 'int close [150010]' redeclared as different kind of entity
  105 |         open[150010], close[150010],
      |                                   ^
In file included from /usr/include/x86_64-linux-gnu/bits/sigstksz.h:24,
                 from /usr/include/signal.h:328,
                 from /usr/include/c++/14/csignal:42,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:116,
                 from a.cc:1:
/usr/include/unistd.h:358:12: note: previous declaration 'int close(int)'
  358 | extern int close (int __fd);
      |            ^~~~~
a.cc: In function 'void makeLCA()':
a.cc:112:34: error: ISO C++ forbids applying 'sizeof' to an expression of function type [-fpermissive]
  112 |         memset(close, -1, sizeof(close));
      |                                 ~^~~~~~
a.cc:112:16: error: invalid conversion from 'int (*)(int)' to 'void*' [-fpermissive]
  112 |         memset(close, -1, sizeof(close));
      |                ^~~~~
      |                |
      |                int (*)(int)
In file included from /usr/include/c++/14/cstring:43,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:121:
/usr/include/string.h:61:28: note:   initializing argument 1 of 'void* memset(void*, int, size_t)'
   61 | extern void *memset (void *__s, int __c, size_t __n) __THROW __nonnull ((1));
      |                      ~~~~~~^~~
a.cc:133:32: warning: pointer to a function used in arithmetic [-Wpointer-arith]
  133 |                         close[v] = close_index[v] = cnt++;
      |                                ^
a.cc:133:34: error: assignment of read-only location '*(close + ((sizetype)v))'
  133 |                         close[v] = close_index[v] = cnt++;
      |                         ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
a.cc: In function 'int main()':
a.cc:191:53: warning: pointer to a function used in arithmetic [-Wpointer-arith]
  191 |                         int o = open[a], c = close[a];
      |                                                     ^
a.cc:191:53: error: invalid conversion from 'int (*)(int)' to 'int' [-fpermissive]
  191 |                         int o = open[a], c = close[a];
      |                                                     ^
      |                                                     |
      |                                                     int (*)(int)