Submission #209785

#	Time	Username	Problem	Language	Result	Execution time	Memory
209785		medk	Sky Walking (IOI19_walk)	C++14	10 / 100	4096 ms	90304 KiB

walk

#include "walk.h"
#include <bits/stdc++.h>

#define ll long long
#define pb push_back
#define x first
#define y second

using namespace std;

int n,m;
vector<vector<int>> twr,br;
vector<pair<ll,ll>> tower;
vector<pair<ll,pair<ll,ll>>> bridge;
map<pair<int,int>,ll> dist;

ll min_distance(vector<int> x, vector<int> h, vector<int> l, vector<int> r, vector<int> y, int s, int g)
{
    n=x.size(), m=l.size();
    twr.resize(n), br.resize(m);
    for(int i=0;i<n;i++) tower.pb({h[i],x[i]});
    for(int i=0;i<m;i++) bridge.pb({y[i],{x[l[i]],x[r[i]]}});
    pair<ll,ll> ps=tower[s], pg=tower[g];
    sort(tower.begin(),tower.end()); reverse(tower.begin(),tower.end());
    sort(bridge.begin(),bridge.end()); reverse(bridge.begin(),bridge.end());
    for(int i=0;i<n;i++)
    {
        if(tower[i]==ps) s=i;
        if(tower[i]==pg) g=i;
    }
    twr[g].pb(-1);
    set<pair<int,int>> st;
    int ptr=0;
    for(int i=0;i<m;i++)
    {
        int H=bridge[i].x,L=bridge[i].y.x,R=bridge[i].y.y;
        if(L>R) swap(L,R);
        while(ptr<n)
        {
            if(tower[ptr].x<H) break;
            st.insert({tower[ptr].y,ptr});
            ptr++;
        }
        auto itL=st.lower_bound({L,-1}), itR=st.lower_bound({R+1,-1});
        while(itL!=itR && itL!=st.end())
        {
            twr[(*itL).y].pb(i);
            br[i].pb((*itL).y);
            itL++;
        }
    }
    set<pair<int,int>> vis;
    dist[{s,-1}]=0;
    priority_queue<pair<pair<ll,pair<int,int>>,bool>> dij;
    dij.push({{0,{s,-1}},1});
    while(!dij.empty())
    {
        ll d=-dij.top().x.x; int T=dij.top().x.y.x, B=dij.top().x.y.y; bool which=dij.top().y;
        dij.pop();
        if(vis.count({T,B})) continue;
        vis.insert({T,B});
        if(which) for(int v:twr[T])
        {
            if(v==B) continue;
            if(vis.count({T,v})) continue;
            ll newD=d+abs((v==-1?0:bridge[v].x)-(B==-1?0:bridge[B].x));
            if(newD<(dist.count({T,v})?dist[{T,v}]:2e18))
            {
                dist[{T,v}]=newD;
                dij.push({{-newD,{T,v}},which^1});
            }
        }
        else if(B!=-1) for(int v:br[B])
        {
            if(v==T) continue;
            if(vis.count({v,B})) continue;
            ll newD=d+abs(tower[v].y-tower[T].y);
            if(newD<(dist.count({v,B})?dist[{v,B}]:2e18))
            {
                dist[{v,B}]=newD;
                dij.push({{-newD,{v,B}},which^1});
            }
        }
    }
    if(dist.count({g,-1})) return dist[{g,-1}];
    return -1;
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 14
• Subtask 3: 0 / 15
• Subtask 4: 0 / 18
• Subtask 5: 0 / 43