제출 #412937

#제출 시각아이디문제언어결과실행 시간메모리
412937LouayFarah꿈 (IOI13_dreaming)C++14
10 / 100
72 ms65540 KiB
#include "bits/stdc++.h" #include "dreaming.h" using namespace std; #define pb push_back #define mp make_pair #define fi first #define se second void dfs1(vector<pair<int, int>> adj[], vector<bool> &visited, int u) { if(visited[u]) return; visited[u] = true; for(auto v: adj[u]) { dfs1(adj, visited, v.fi); } } pair<int, int> extract_components(vector<pair<int, int>> adj[], int N) { vector<int> temp; vector<bool> visited(N, false); for(int i = 0; i<N; i++) { if(!visited[i]) { dfs1(adj, visited, i); temp.pb(i); } } pair<int, int> res = mp(0, 0); temp[0], res.se = temp[1]; return res; } void depth(vector<pair<int, int>> adj[], vector<bool> visited, vector<int> &cnt, int u) { visited[u] = true; for(auto v: adj[u]) { if(!visited[v.fi]) { cnt[v.fi] = cnt[u] + v.se; depth(adj, visited, cnt, v.fi); } } } pair<int, int> diameter(vector<pair<int, int>> adj[], int N, int u) { int a = u, b = u, c = u; int maxi = 0; vector<bool> visited(N, false); vector<int> cnt(N, 0); depth(adj, visited, cnt, a); for(int i = 0; i<N; i++) { if(maxi<cnt[i]) { maxi = cnt[i]; b = i; } } cnt.assign(N, 0); visited.assign(N, false); depth(adj, visited, cnt, b); maxi = 0; for(int i = 0; i<N; i++) { if(maxi<cnt[i]) { maxi = cnt[i]; c = i; } } return mp(b, c); } vector<int> bfs(vector<pair<int, int>> adj[], int N, pair<int, int> d) { int st = d.fi, en = d.se; if(st==en) { vector<int> temp; temp.pb(st); return temp; } vector<bool> visited(N, false); vector<int> parent(N, -1); queue<int> q; q.push(st); visited[st] = true; bool flag = true; while(!q.empty()&&flag) { int u = q.front(); q.pop(); for(auto v: adj[u]) { if(visited[v.fi]) continue; visited[v.fi] = true; parent[v.fi] = u; q.push(v.fi); if(v.fi==en) flag = false; } } vector<int> path; while(parent[en]!=-1) { path.pb(en); en = parent[en]; } path.pb(st); reverse(path.begin(), path.end()); return path; } int solve(vector<pair<int, int>> adj[], int N) { int a = 0, b = 0; int maxi = 0; vector<bool> visited(N, false); vector<int> cnt(N, 0); depth(adj, visited, cnt, a); for(int i = 0; i<N; i++) { if(maxi<cnt[i]) { maxi = cnt[i]; b = i; } } cnt.assign(N, 0); visited.assign(N, false); depth(adj, visited, cnt, b); maxi = 0; for(int i = 0; i<N; i++) { if(maxi<cnt[i]) { maxi = cnt[i]; } } return maxi; } int travelTime(int N, int M, int L, int A[], int B[], int T[]) { vector<pair<int, int>> adj[N]; for(int i = 0; i<M; i++) { adj[A[i]].pb(mp(B[i], T[i])); adj[B[i]].pb(mp(A[i], T[i])); } pair<int, int> comps = extract_components(adj, N); int a = comps.fi, b = comps.se; pair<int, int> d1 = diameter(adj, N, a); pair<int, int> d2 = diameter(adj, N, b); vector<int> path1, path2; path1 = bfs(adj, N, d1); path2 = bfs(adj, N, d2); int len1 = int(path1.size()); int len2 = int(path2.size()); vector<bool> visited(N, false); vector<int> cnt1(N, 0), cnt2(N, 0); depth(adj, visited, cnt1, path1[0]); depth(adj, visited, cnt2, path2[0]); int n1 = path1[0], n2 = path2[0]; int dif = 1e8; for(int i = 1; i<len1; i++) { if(abs(cnt1[path1[i]]-(cnt1[path1[len1-1]]-cnt1[path1[i]]))<dif) { dif = abs(cnt1[path1[i]]-(cnt1[path1[len1-1]]-cnt1[path1[i]])); n1 = path1[i]; } } dif = 1e8; for(int i = 1; i<len2; i++) { if(abs(cnt2[path2[i]]-(cnt2[path2[len2-1]]-cnt2[path2[i]]))<dif) { dif = abs(cnt2[path2[i]]-(cnt2[path2[len2-1]]-cnt2[path2[i]])); n2 = path2[i]; } } path1.clear(); path2.clear(); cnt1.clear(); cnt2.clear(); adj[n1].pb(mp(n2, L)); adj[n2].pb(mp(n1, L)); int res = solve(adj, N); return res; }
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