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int tree[2*N];
vector euler;
int first[N], last[N];
int H[N], P[N][LG_N];
int val[N];
void dfs(int u, int p, int h) {
H[u] = h;
P[u][0] = p;
for(int i = 1;i < LG_N;i++) {
P[u][i] = P[P[u][i-1]][i-1];
}
first[u] = euler.size();
euler.push_back(u);
for(int v : adj[u]) {
if(v == p) {
continue;
}
dfs(v, u, h+1);
}
last[u] = euler.size();
euler.push_back(u);
}
int lca(int u, int v) {
if(H[u] < H[v]) swap(u, v);
for(int i = LG_N-1;i >= 0;i--) {
if(H[P[u][i]] >= H[v]) {
u = P[u][i];
}
}
if(u == v) {
return u;
}
for(int i = LG_N-1;i >= 0;i--) {
if(P[u][i] != P[v][i]) {
u = P[u][i];
v = P[v][i];
}
}
return P[u][0];
}
void update(int idx, int val) {
while(idx < euler.size()) {
tree[idx] += val;
idx += idx & (-idx);
}
}
int query(int idx) {
int ans = 0;
while(idx > 0) {
ans += tree[idx];
idx -= idx & (-idx);
}
return ans;
}
int main() {
ios::sync_with_stdio(false);
cin >> n >> q;
for(int i = 0;i < n-1;i++) {
int u, v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
euler.resize(1, 0);
dfs(0, 0, 0);
for(int i = 0;i < q;i++) {
int type;
cin >> type;
if(type == 1) {
int u, x;
cin >> u >> x;
update(first[u], x - val[u]);
update(last[u], val[u] - x);
val[u] = x;
}else {
int u, v;
cin >> u >> v;
int l = lca(u, v);
int ans = query(first[u]) + query(first[v]);
ans = ans - 2 * query(first[l]) + val[l];
cout << ans << "\n";
}
}
return 0;
}
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Lazy White Falcon
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include
include
include
include
include
using namespace std;
const int N = 100010; const int LG_N = 20;
vector adj[N]; int n, q;
int tree[2*N]; vector euler; int first[N], last[N];
int H[N], P[N][LG_N]; int val[N];
void dfs(int u, int p, int h) { H[u] = h; P[u][0] = p; for(int i = 1;i < LG_N;i++) { P[u][i] = P[P[u][i-1]][i-1]; } first[u] = euler.size(); euler.push_back(u); for(int v : adj[u]) { if(v == p) { continue; } dfs(v, u, h+1); } last[u] = euler.size(); euler.push_back(u); } int lca(int u, int v) { if(H[u] < H[v]) swap(u, v); for(int i = LG_N-1;i >= 0;i--) { if(H[P[u][i]] >= H[v]) { u = P[u][i]; }
} if(u == v) { return u; } for(int i = LG_N-1;i >= 0;i--) { if(P[u][i] != P[v][i]) { u = P[u][i]; v = P[v][i]; } } return P[u][0]; } void update(int idx, int val) { while(idx < euler.size()) { tree[idx] += val; idx += idx & (-idx); } } int query(int idx) { int ans = 0; while(idx > 0) { ans += tree[idx]; idx -= idx & (-idx); } return ans; } int main() {
}