Submission #760344

#	Time	Username	Problem	Language	Result	Execution time	Memory
760344		NK_	Birthday gift (IZhO18_treearray)	C++17	100 / 100	735 ms	75716 KiB

treearray

// 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 f first
#define s second
#define mp make_pair
 
using pi = pair<int, int>;
 
const int nax = 2e5+5;
const int LG = 18;
 
template<class T> using V = vector<T>;
 
int up[nax][LG];
int dep[nax];
 
int jmp(int u, int d) {
	for(int i = 0; i < LG; i++) if ((d >> i) & 1) {
		u = up[u][i];
	}
	return u;
}
 
int lca(int a, int b) {
	if (dep[a] < dep[b]) swap(a, b);
 
	a = jmp(a, dep[a] - dep[b]);
	if (a == b) return a;
 
	for(int i = LG - 1; i >= 0; i--) {
		if (up[a][i] != up[b][i]) a = up[a][i], b = up[b][i];
	}
 
	return up[a][0];
}
 
int main() {
	cin.tie(0)->sync_with_stdio(0);
	
	int N, M, Q; scanf("%d %d %d", &N, &M, &Q);
 
	V<V<int>> adj(N);
	for(int _ = 0; _ < N-1; _++) {
		int u, v; scanf("%d %d", &u, &v); --u, --v;
		adj[u].pb(v);
		adj[v].pb(u);
	}
 
	function<void(int, int)> dfs = [&](int u, int p) {
		up[u][0] = p;
		for(int i = 1; i < LG; i++) up[u][i] = up[up[u][i-1]][i-1];
 
		for(auto v : adj[u]) if (v != p) {
			dep[v] = dep[u] + 1; dfs(v, u);
		}
	};
 
	dep[0] = 0; dfs(0, 0);
 
	V<set<pi>> X(N);
	V<int> A(M), LCA(M-1); for(auto& x : A) { scanf("%d", &x); --x; }
 
	for(int i = 0; i < M; i++) {
		if (i+1 < M) X[(LCA[i] = lca(A[i], A[i+1]))].insert(mp(i, i+1));
		X[A[i]].insert(mp(i, i));
	}
 
	while(Q--) {
		int t; scanf("%d", &t);
		if (t == 1) {
			int i, x; scanf("%d %d", &i, &x); --i, --x;
			if (i-1 >= 0) X[LCA[i-1]].erase(mp(i-1, i));
			if (i+1 < M) X[LCA[i]].erase(mp(i, i+1));
			X[A[i]].erase(mp(i, i));
 
			A[i] = x;
 
			X[A[i]].insert(mp(i, i));
			if (i-1 >= 0) X[(LCA[i-1] = lca(A[i-1], A[i]))].insert(mp(i-1, i));
			if (i+1 < M) X[(LCA[i] = lca(A[i], A[i+1]))].insert(mp(i, i+1));
		} else {
			int l, r, x; scanf("%d %d %d", &l, &r, &x); --l, --r, --x;
			// --r; // BECAUSE NEED TO FIND i SUCH THAT l ≤ i < r
 
			// for(auto v : X[x]) cout << "(" << v.f << ", " << v.s  << ")" << nl;
			// cout << nl;
 
			auto it = X[x].lower_bound(mp(l, -1));
			if (it == end(X[x])) printf("-1 -1\n");
			else {
				int L, R; tie(L, R) = *it;
				if (R > r) L = R = -1;
				else ++L, ++R;
				printf("%d %d\n", L, R);
			}
		}
	}
 
 
 
 
    return 0;
}

Compilation message (stderr)

treearray.cpp: In function 'int main()':
treearray.cpp:46:20: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |  int N, M, Q; scanf("%d %d %d", &N, &M, &Q);
      |               ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
treearray.cpp:50:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |   int u, v; scanf("%d %d", &u, &v); --u, --v;
      |             ~~~~~^~~~~~~~~~~~~~~~~
treearray.cpp:67:49: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   67 |  V<int> A(M), LCA(M-1); for(auto& x : A) { scanf("%d", &x); --x; }
      |                                            ~~~~~^~~~~~~~~~
treearray.cpp:75:15: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   75 |   int t; scanf("%d", &t);
      |          ~~~~~^~~~~~~~~~
treearray.cpp:77:19: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |    int i, x; scanf("%d %d", &i, &x); --i, --x;
      |              ~~~~~^~~~~~~~~~~~~~~~~
treearray.cpp:88:22: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   88 |    int l, r, x; scanf("%d %d %d", &l, &r, &x); --l, --r, --x;
      |                 ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 18 / 18
• Subtask 3: 26 / 26
• Subtask 4: 44 / 44