// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>
using namespace std;
#define nl '\n'
#define pb push_back
#define pf push_front
#define mp make_pair
#define f first
#define s second
#define sz(x) int(x.size())
template<class T> using V = vector<T>;
using pi = pair<int, int>;
using vi = V<int>;
using vpi = V<pi>;
using ll = long long;
using pl = pair<ll, ll>;
using vpl = V<pl>;
using vl = V<ll>;
using db = long double;
template<class T> using pq = priority_queue<T, V<T>, greater<T>>;
const int MOD = 1e9 + 7;
const ll INFL = ll(1e17);
// START OF SEGTREE
struct Seg {
const ll ID = INFL, IDL = 0; ll comb(ll a, ll b) { return min(a, b); }
int n; vl seg, lazy;
void init(int N) {
n = 1; while(n < N) n *= 2;
seg.assign(2*n, ID); lazy.assign(2*n, IDL);
}
void pull(int x) { seg[x] = comb(seg[2*x], seg[2*x+1]); }
void push(int x, int L, int R) {
seg[x] += lazy[x];
if (L != R) for(int i = 0; i < 2; i++) lazy[2*x+i] += lazy[x];
lazy[x] = IDL;
}
void upd(int l, int r, ll v, int x, int L, int R) {
push(x, L, R); if (r < L || R < l) return;
if (l <= L && R <= r) {
lazy[x] = v; push(x, L, R); return;
}
int M = (L + R) / 2;
upd(l, r, v, 2*x, L, M);
upd(l, r, v, 2*x+1, M+1, R);
pull(x);
}
ll query(int l, int r, int x, int L, int R) {
push(x, L, R); if (r < L || R < l) return 2 * ID;
if (l <= L && R <= r) return seg[x];
int M = (L + R) / 2;
return comb(query(l, r, 2*x, L, M), query(l, r, 2*x+1, M+1, R));
}
void upd(int l, int r, ll v) { upd(l, r, v, 1, 0, n - 1); }
ll query(int l, int r) { return query(l, r, 1, 0, n - 1); }
ll query() { return seg[1]; }
};
// END OF SEGTREE
const int nax = 1e5 + 5;
// MAIN
vpi adj[nax]; int W[nax];
// CENTROID
int sub[nax], proc[nax], siz[nax];
// CENTROID SUBTREES
const int LG = 17;
int eid[nax][LG], st[nax][LG], en[nax][LG], par[nax][LG], L[nax];
Seg T[nax];
// __[u][t] = a property of the subtree rooted at u's t-th parent in the centroid tree
// START OF CENTROID
void gen(int u, int p = -1) {
sub[u] = 1;
for(auto& e : adj[u]) {
int v, i; tie(v, i) = e;
if (v != p && !proc[v]) {
gen(v, u); sub[u] += sub[v];
}
}
}
int t = 0, C = -1;
int LVL = 0;
void dfs(int u, int p = -1) {
par[u][LVL] = C; st[u][LVL] = t++;
for(auto& e : adj[u]) {
int v, i; tie(v, i) = e;
if (v != p && !proc[v]) {
eid[v][LVL] = i;
dfs(v, u); sub[u] += sub[v];
}
}
en[u][LVL] = t - 1;
}
int find(int u, int n, int p = -1) {
for(auto& e : adj[u]) {
int v, i; tie(v, i) = e;
if (v != p && !proc[v]) {
if (2 * sub[v] > n) return find(v, n, u);
}
}
return u;
}
int init(int u = 0) {
gen(u); int c = find(u, sub[u]);
t = 0, C = c, eid[c][LVL] = -1; dfs(c);
proc[c] = 1, L[u] = LVL;
siz[c] = sub[u];
assert(t <= siz[c]);
T[c].init(siz[c]);
for(auto& e : adj[c]) {
int v, i; tie(v, i) = e;
if (!proc[v]) {
++LVL; init(v); --LVL;
}
}
return c;
}
// END OF CENTROID
int main() {
cin.tie(0)->sync_with_stdio(0);
memset(par, -1, sizeof(par));
int N, Q; cin >> N >> Q;
unordered_map<ll, int> E;
for(int i = 0; i < N - 1; i++) {
int u, v; cin >> u >> v >> W[i]; --u, --v;
adj[u].pb(mp(v, i));
adj[v].pb(mp(u, i));
E[u * 1LL * N + v] = E[v * 1LL * N + u] = i;
}
int R = init();
for(int u = 0; u < N; u++) {
for(int p = 0; p <= L[u]; p++) {
int e = eid[u][p], x = par[u][p]; if (x == -1) continue;
if (e != -1) T[x].upd(st[u][p], en[u][p], W[e]);
}
}
for(int q = 0; q < Q; q++) {
int type; cin >> type;
if (type == 1) {
int u; cin >> u; --u;
ll ans = 2 * INFL;
for(int p = 0; p <= L[u]; p++) {
int x = par[u][p], pos = st[u][p];
if (x == -1) continue;
ll dst = T[x].query(pos, pos);
if (dst >= INFL) dst -= INFL;
ans = min(ans, dst + T[x].query());
}
cout << (ans >= INFL ? -1 : ans) << nl;
}
if (type == 2) {
int u; cin >> u; --u;
for(int p = 0; p <= L[u]; p++) {
int x = par[u][p], pos = st[u][p];
if (x == -1) continue;
if (T[x].query(pos, pos) >= INFL) T[x].upd(pos, pos, -INFL);
else T[x].upd(pos, pos, +INFL);
}
}
if (type == 3) {
int u, v, w; cin >> u >> v >> w; --u, --v;
int i = E[u * 1LL * N + v];
for(int rep = 0; rep < 2; rep++) {
for(int p = 0; p <= L[u]; p++) {
int x = par[u][p], e = eid[u][p]; if (x == -1) continue;
if (e == i) T[x].upd(st[u][p], en[u][p], w - W[i]);
}
swap(u, v);
}
W[i] = w;
}
}
return 0;
}
Compilation message
Main.cpp: In function 'int main()':
Main.cpp:159:6: warning: unused variable 'R' [-Wunused-variable]
159 | int R = init();
| ^
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
14 ms |
17876 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
1127 ms |
115468 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
1482 ms |
526136 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
1188 ms |
125428 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
1206 ms |
123924 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
14 ms |
17876 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |