Submission #778531

#TimeUsernameProblemLanguageResultExecution timeMemory
778531jasminSky Walking (IOI19_walk)C++17
0 / 100
15 ms3136 KiB
#include "walk.h" #include<bits/stdc++.h> using namespace std; const long long INF=1e18; int distance(int i, int h, int j, int h2, vector<int>& x){ return abs(x[i]-x[j]) + abs(h-h2); } long long dijkstra(int n, map<int, map<int, vector<pair<int,int> > > >& adi, int a, int b, vector<int>& x){ map<int, map<int, long long> > dist; //plus 1 dist[a][0]=1; map<int, map<int, bool> > vis; priority_queue<pair<long long, pair<int,int> > > pq; pq.push({-1, {a, 0}}); while(!pq.empty()){ auto [v, h] = pq.top().second; pq.pop(); if(vis[v][h]) continue; vis[v][h]=true; for(auto [u, h2]: adi[v][h]){ if(dist[u][h2]==0 || dist[v][h]+distance(v, h, u, h2, x)<dist[u][h2]){ dist[u][h2] = dist[v][h] + distance(v, h, u, h2, x); pq.push({-dist[u][h2], {u, h2}}); } } } return dist[b][0]-1; } long long min_distance(vector<int> x, vector<int> h, vector<int> l, vector<int> r, vector<int> y, int s, int g) { int n=x.size(); int m=l.size(); vector<int> sorth(n, 0); iota(sorth.begin(), sorth.end(), 0); sort(sorth.begin(), sorth.end(), [&](int i, int j){ return h[i]<h[j]; }); vector<int> sorty(m, 0); iota(sorty.begin(), sorty.end(), 0); sort(sorty.begin(), sorty.end(), [&](int i, int j){ return y[i]<y[j]; }); set<pair<int, int> > active; for(int i=0; i<n; i++){ active.insert({x[i], i}); } int j=0; map<int, map<int, vector<pair<int,int> > > > adi; vector<set<int> > hights(n, {0}); for(auto i: sorty){ while(j<n && h[sorth[j]] < y[i]){ active.erase({x[sorth[j]], sorth[j]}); j++; } auto p = active.lower_bound({l[i], 0}); while(next(p)!=active.end() && (*next(p)).first<=r[i]){ //horizontal conection int ind=(*p).second; int ind2=(*next(p)).second; adi[ind][y[i]].push_back({ind2, y[i]}); hights[ind].insert(y[i]); adi[ind2][y[i]].push_back({ind, y[i]}); hights[ind2].insert(y[i]); p=next(p); } } for(int i=0; i<n; i++){ int last=*hights[i].begin(); for(auto e: hights[i]){ if(e==last) continue; adi[i][last].push_back({i, e}); adi[i][e].push_back({i, last}); last=e; } } return dijkstra(n, adi, s, g, x); }
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