結果
問題 | No.1212 Second Path |
ユーザー |
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提出日時 | 2020-08-30 15:24:41 |
言語 | C++11 (gcc 13.3.0) |
結果 |
AC
|
実行時間 | 342 ms / 3,000 ms |
コード長 | 3,801 bytes |
コンパイル時間 | 1,642 ms |
コンパイル使用メモリ | 92,424 KB |
実行使用メモリ | 59,604 KB |
最終ジャッジ日時 | 2024-11-15 08:55:44 |
合計ジャッジ時間 | 14,662 ms |
ジャッジサーバーID (参考情報) |
judge5 / judge4 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 3 |
other | AC * 45 |
ソースコード
#include <iostream>#include <cstdio>#include <cmath>#include <ctime>#include <cstdlib>#include <cassert>#include <vector>#include <list>#include <stack>#include <queue>#include <deque>#include <map>#include <set>#include <bitset>#include <string>#include <algorithm>#include <utility>#define llint long long#define inf 1e18#define rep(x, s, t) for(llint (x) = (s); (x) < (t); (x)++)#define Rep(x, s, t) for(llint (x) = (s); (x) <= (t); (x)++)#define chmin(x, y) (x) = min((x), (y))#define chmax(x, y) (x) = max((x), (y))#define mod 1000000007using namespace std;typedef pair<llint, llint> P;struct edge{llint to, cost;edge(){}edge(llint a, llint b){to = a, cost = b;}};llint n, Q;vector<edge> G[100005];set<P> S[100005];int Prev[200005][18];llint depth[200005], dist[200005], pcost[200005];llint mini[200005][18];int getLCA(int u, int v){int x = u, y = v;if(depth[y] > depth[x]) swap(x, y);for(int i = 17; i >= 0; i--){if(depth[x] - (1<<i) >= depth[y]) x = Prev[x][i];}if(x == y) return x;for(int i = 17; i >= 0; i--){if(Prev[x][i] != Prev[y][i]){x = Prev[x][i];y = Prev[y][i];}}x = Prev[x][0];return x;}void predfs(int v, int p, int d, llint s, llint pc){depth[v] = d, dist[v] = s, Prev[v][0] = p, pcost[v] = pc;for(int i = 0; i < G[v].size(); i++){if(G[v][i].to == p) continue;predfs(G[v][i].to, v, d+1, s + G[v][i].cost, G[v][i].cost);S[v].insert(P(G[v][i].cost, G[v][i].to));}}int main(void){ios::sync_with_stdio(0);cin.tie(0);cin >> n;llint u, v, w;for(int i = 1; i <= n-1; i++){cin >> u >> v >> w;G[u].push_back(edge(v, w));G[v].push_back(edge(u, w));}predfs(1, 0, 0, 0, inf);for(int i = 1; i < 18; i++){for(int j = 1; j <= n; j++){Prev[j][i] = Prev[Prev[j][i-1]][i-1];}}for(int i = 1; i <= n; i++){llint p = Prev[i][0]; mini[i][0] = inf;if(p == 0) continue;for(auto it = S[p].begin(); it != S[p].end(); it++){if(it->second != i){mini[i][0] = it->first;break;}}}for(int i = 1; i < 18; i++){for(int j = 1; j <= n; j++){mini[j][i] = mini[j][i-1];if(Prev[j][i-1]) chmin(mini[j][i], mini[Prev[j][i-1]][i-1]);}}/*for(int i = 0; i < 18; i++){for(int j = 1; j <= n; j++){cout << mini[j][i] << " ";}cout << endl;}*/cin >> Q;llint x, y;for(int q = 0; q < Q; q++){cin >> x >> y;llint lca = getLCA(x, y), mn = inf, ans = dist[x]+dist[y]-2*dist[lca];//cout << "Q " << x << " " << y << endl;//cout << lca << " " << ans << endl;if(lca != x && lca != y){if(S[x].size()) mn = min(mn, S[x].begin()->first);if(S[y].size()) mn = min(mn, S[y].begin()->first);llint rem = depth[x] - depth[lca] - 1, v = x, w = y;for(int i = 17; i >= 0; i--){if(rem & (1<<i)){mn = min(mn, mini[v][i]);v = Prev[v][i];}}rem = depth[y] - depth[lca] - 1;for(int i = 17; i >= 0; i--){if(rem & (1<<i)){mn = min(mn, mini[w][i]);w = Prev[w][i];}}//cout << u << " " << v << endl;for(auto it = S[lca].begin(); it != S[lca].end(); it++){if(it->second != v && it->second != w){mn = min(mn, it->first);break;}}mn = min(mn, pcost[lca]);}else{if(lca == y) swap(x, y);if(S[y].size()) mn = min(mn, S[y].begin()->first);llint rem = depth[y] - depth[lca] - 1, w = y;for(int i = 17; i >= 0; i--){if(rem & (1<<i)){mn = min(mn, mini[w][i]);w = Prev[w][i];}}for(auto it = S[x].begin(); it != S[x].end(); it++){if(it->second != w){mn = min(mn, it->first);break;}}mn = min(mn, pcost[lca]);}if(mn > inf/2) cout << -1 << "\n";else{ans += mn*2;cout << ans << "\n";}}flush(cout);return 0;}