結果

問題 No.898 tri-βutree
ユーザー polylogKpolylogK
提出日時 2019-09-16 23:48:55
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 304 ms / 4,000 ms
コード長 2,538 bytes
コンパイル時間 2,218 ms
コンパイル使用メモリ 187,544 KB
実行使用メモリ 28,952 KB
最終ジャッジ日時 2024-11-08 21:37:40
合計ジャッジ時間 9,398 ms
ジャッジサーバーID
(参考情報)
judge5 / judge1
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
sample AC * 1
other AC * 21
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#include <bits/stdc++.h>
using namespace std::literals::string_literals;
using i64 = long long;
using std::cout;
using std::endl;
using std::cin;
template<typename T>
std::vector<T> make_v(size_t a){return std::vector<T>(a);}
template<typename T,typename... Ts>
auto make_v(size_t a,Ts... ts){
return std::vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));
}
struct LowestCommonAncestor{
std::vector<std::vector<int>> g, parent;
std::vector<int> depth;
bool built = false;
int N;
const int logN = 20;
LowestCommonAncestor(int n) : N(n) {
g.resize(N);
parent.resize(logN, std::vector<int>(N));
depth.resize(N);
}
void add_edge(int u, int v){
g[u].push_back(v);
g[v].push_back(u);
}
void dfs(int v, int par = -1, int d = 0){
parent[0][v] = par;
depth[v] = d;
for(auto e:g[v]){
if(e == par) continue;
dfs(e, v, d + 1);
}
}
void build(){
dfs(0);
for(int k = 0; k < logN - 1; k++){
for(int i = 0; i < N; i++){
if(parent[k][i] < 0) parent[k + 1][i] = -1;
else parent[k + 1][i] = parent[k][parent[k][i]];
}
}
}
int get(int u, int v){
if(!built) build(); built = true;
if(depth[u] > depth[v]) std::swap(u, v);
for(int k = 0; k < logN; k++){
if(((depth[v] - depth[u]) >> k) & 1){
v = parent[k][v];
}
}
if(u == v) return u;
for(int k = logN - 1; k >= 0; k--){
if(parent[k][u] == parent[k][v]) continue;
u = parent[k][u];
v = parent[k][v];
}
return parent[0][u];
}
};
int main() {
// input
int n; scanf("%d", &n);
assert(1 <= n and n <= (int)1e5);
LowestCommonAncestor lca(n);
std::vector<std::vector<std::pair<int, i64>>> g(n);
for(int i = 0; i < n - 1; i++) {
int a, b, c; scanf("%d%d%d", &a, &b, &c);
assert(0 <= a and a < n);
assert(0 <= b and b < n);
assert(1 <= c and c <= (int)1e9);
g[a].push_back({b, c});
g[b].push_back({a, c});
lca.add_edge(a, b);
}
lca.build();
// solve
std::vector<i64> dist(n);
auto dfs = [&](auto && dfs, int v, int par) -> void {
for(auto e: g[v]) {
if(e.first == par) continue;
dist[e.first] = dist[v] + e.second;
dfs(dfs, e.first, v);
}
};
dfs(dfs, 0, -1);
auto calc = [&lca, dist](const int & x, const int & y) -> i64 {
return dist[x] + dist[y] - 2LL * dist[lca.get(x, y)];
};
int q; scanf("%d", &q);
while(q--) {
int x, y, z; scanf("%d%d%d", &x, &y, &z);
assert(0 <= x and x < n);
assert(0 <= y and y < n);
assert(0 <= z and z < n);
printf("%lld\n", (calc(x, y) + calc(y, z) + calc(z, x)) >> 1);
}
return 0;
}
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