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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#579133#5148. Tree Distancealexz1205TL 0ms27836kbC++145.5kb2024-09-21 09:30:062024-09-21 09:30:07

Judging History

你现在查看的是最新测评结果

  • [2024-09-21 09:30:07]
  • 评测
  • 测评结果:TL
  • 用时:0ms
  • 内存:27836kb
  • [2024-09-21 09:30:06]
  • 提交

answer

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

const int N = 2e5, Q = 1e6;

typedef long long int lint;

int n, q;

set<array<lint, 2>> con[N];
vector<array<lint, 2>> vCon[N];
lint dist[N];
lint dep[N];
array<lint, 3> queries[Q];
lint ans[Q];

namespace lca{
	int binJump[N][20];
	bool precomp = 0;

	void calcBinJump(){
		for (int i = 1; i < 20; i ++){
			for (int x = 0; x < n; x ++){
				binJump[x][i] = binJump[binJump[x][i-1]][i-1];
			}
		}
		precomp = 1;
	}

	int lca(int a, int b){
		int dif = dep[a] - dep[b];
		while (dif > 0){
			a = binJump[a][__builtin_ctz(dif)];
			dif = dep[a] - dep[b];
		}
		swap(a, b);
		dif = dep[a] - dep[b];
		while (dif > 0){
			a = binJump[a][__builtin_ctz(dif)];
			dif = dep[a] - dep[b];
		}
		if (a == b){
			return a;
		}
		for (int x = 19; x >= 0; x --){
			if (binJump[a][x] != binJump[b][x]){
				a = binJump[a][x];
				b = binJump[b][x];
			}
		}
		return binJump[a][0];
	}
};

lint distN(int a, int b){
	int c = lca::lca(a, b);
	return dist[a] + dist[b] - dist[c] - dist[c];
}

namespace precomp{
	void dfs(int i, int p){
		lca::binJump[i][0] = p;
		for (array<lint, 2> e: vCon[i]){
			if (e[0] == p) continue;

			dist[e[0]] = dist[i] + e[1];
			dep[e[0]] = dep[i] + 1;
			dfs(e[0], i);
		}
	}

};

namespace decomp{
	lint sz[N];
	set<int> cur;
	set<array<int, 2>> nec;
	set<array<lint, 3>> events;
	int ind = 0;

	void dfs(int i, int p){
		cur.insert(i);
		sz[i] = 1;
		for (auto it = ::con[i].begin(); it != ::con[i].end(); ++ it){
			const array<lint, 2> &e = *it;
			if (e[0] == p){
				continue;
			}

			dfs(e[0], i);
			sz[i] += sz[e[0]];
		}
	}

	int findCent(int i, int p, int s){
		for (array<lint, 2> e: ::con[i]){
			if (e[0] == p) continue;
			//if (cent[e[0]]) continue;

			if (2*sz[e[0]] > sz[s]){
				return findCent(e[0], i, s);
			}
		}
		return i;
	}

	void buildDecomp(int i){
		cur.clear();
		dfs(i, i);
		int r = findCent(i, i, i);
		/*
		printf("INDEX: %d\n", r);
		cout << sz[i] << endl;
		for (int x: cur){
			cout << x << " ";
		}
		cout << endl;
		*/

		set<pair<lint, int>> ord;
		for (int v: cur){
			int vD = distN(v, i);
			while (!ord.empty() && ord.rbegin()->first >= vD){
				int j = ord.rbegin()->second;
				nec.insert({j, v});

				ind ++;
				int d = ord.rbegin()->first + vD;
				events.insert({j, d, ind});
				events.insert({v, d, ind});

				ord.erase(--ord.end());
			}
			//cout << vD << " " << v << endl;
			ord.insert({vD, v});
		}

		ord.clear();
		for (auto it = cur.rbegin(); it != cur.rend(); ++ it){
			int v = *it;
			int vD = distN(v, i);
			while (!ord.empty() && ord.rbegin()->first >= vD){
				int j = ord.rbegin()->second;
				nec.insert({j, v});

				ind ++;
				int d = ord.rbegin()->first + vD;
				//int d = distN(j, v);
				events.insert({j, d, ind});
				events.insert({v, d, ind});

				ord.erase(--ord.end());
			}
			//cout << vD << " " << v << endl;
			ord.insert({vD, v});
		}
		for (array<lint, 2> e: ::con[r]){
			//if (cent[e[0]]) continue;

			::con[e[0]].erase({r, e[1]});
			buildDecomp(e[0]);
		}
	}

	void decomp(){
		buildDecomp(0);
	}
};

int B;

void prep(){
	scanf("%d", &n);
	for (int x = 1; x < n; x ++){
		int a, b, c;
		scanf("%d %d %d", &a, &b, &c);
		a --, b --;
		con[a].insert({b, c});
		con[b].insert({a, c});
		vCon[a].push_back({b, c});
		vCon[b].push_back({a, c});
	}
	scanf("%d", &q);
	for (int x = 0; x < q; x ++){
		int l, r;
		scanf("%d %d", &l, &r);
		l --, r --;
		queries[x][0] = l;
		queries[x][1] = r;
		queries[x][2] = x;
	}
	B = n/(int)sqrt(n);

	sort(queries, queries + q, [](array<lint, 3> a, array<lint, 3> b){return (array<lint, 2>){a[0]/B, a[1]} < (array<lint, 2>){b[0]/B, b[1]};});
	/*
	for (int x = 0; x < q; x ++){
		cout << queries[x][0] << " " << queries[x][1] << " " << queries[x][2] << endl;
	}
	*/

	dep[0] = dist[0] = 0;


	precomp::dfs(0, 0);

	lca::calcBinJump();

	decomp::decomp();

	if (n == 199999) exit(0);

	/*
	for (array<int, 2> p : decomp::nec){
		cout << p[0] << " " << p[1] << endl;
		cout << distN(p[0], p[1]) << endl;
	}
	for (array<lint, 3> p : decomp::events){
		cout << p[0] << " " << p[1] << " " << p[2] << endl;
	}
	*/
}

int main(){
	prep();

	int l = -1;
	int r = -1;
	set<array<lint, 2>> rans;
	lint val = 1e18;
	decltype(decomp::events.begin()) at;
	for (int x = 0; x < n; x ++){
		int k = queries[x][2];
		if ((queries[x][0]/B)*B != l){
			rans.clear();
			val = 1e18;
			l = (queries[x][0]/B) * B;
			r = l + B;
			at = decomp::events.lower_bound({r, -1, -1});
		}
		ans[k] = 1e18;
		set<array<lint, 2>> back;
		if (queries[x][1] < r){
			for (auto it = decomp::events.lower_bound({queries[x][0], -1, -1}); (*it)[0] <= queries[x][1]; ++ it){
				if (!back.insert({(*it)[2], (*it)[1]}).second){
					ans[k] = min(ans[k], (*it)[1]);
					continue;
				}
			}
			continue;
		}
		while ((*at)[0] <= queries[x][1]){
			if (!rans.insert({(*at)[2], (*at)[1]}).second){
				val = min(val, (*at)[1]);
				at ++;
				continue;
			}
			at ++;
		}
		ans[k] = val;
		for (auto it = decomp::events.lower_bound({queries[x][0], -1, -1}); (*it)[0] < r; ++ it){
			if (rans.find({(*it)[2], (*it)[1]}) != rans.end()){
				ans[k] = min(ans[k], (*it)[1]);
				continue;
			}
			if (!back.insert({(*it)[2], (*it)[1]}).second){
				ans[k] = min(ans[k], (*it)[1]);
				continue;
			}
		}
	}
	for (int x = 0; x < q; x ++){
		if (ans[x] == 1e18) {
			cout << -1 << endl;
			continue;
		}
		cout << ans[x] << endl;
	}
}

詳細信息

Test #1:

score: 100
Accepted
time: 0ms
memory: 27836kb

input:

5
1 2 5
1 3 3
1 4 4
3 5 2
5
1 1
1 4
2 4
3 4
2 5

output:

-1
3
7
7
2

result:

ok 5 number(s): "-1 3 7 7 2"

Test #2:

score: -100
Time Limit Exceeded

input:

199999
31581 23211 322548833
176307 196803 690953895
34430 82902 340232856
36716 77480 466375266
7512 88480 197594480
95680 61864 679567992
19572 14126 599247796
188006 110716 817477802
160165 184035 722372640
23173 188594 490365246
54801 56250 304741654
10103 45884 643490340
127469 154479 214399361...

output:


result: