Submission #902132

#	Time	Username	Problem	Language	Result	Execution time	Memory
902132		abcvuitunggio	Sky Walking (IOI19_walk)	C++17	100 / 100	1493 ms	179956 KiB

walk

#include "walk.h"
#include <bits/stdc++.h>
#define int long long
using namespace std;
const int INF=1e18;
priority_queue <pair <int, int>, vector <pair <int, int>>, greater <pair <int, int>>> q;
vector <int> a[100001],b[1000001],V;
vector <int32_t> x,h,l,r,y;
vector <pair <int, int>> ke[1000001],ve;
vector <pair <int32_t, int32_t>> nodes;
int n,m,d[1000001];
set <int> S;
void add(int i, int j){
    a[i].push_back(j);
    nodes.push_back({x[i],(j==-1?0:y[j])});
}
int f(int i, int j){
    return lower_bound(nodes.begin(),nodes.end(),make_pair(x[i],(j==-1?0:y[j])))-nodes.begin();
}
void reconnect(int32_t s, int mode){
    vector <pair <int32_t, int32_t>> tmp,changes;
    for (int i=s;(mode?i<n:i>=0);i+=mode*2-1)
        if (tmp.empty()||h[i]>tmp.back().first)
            tmp.push_back({h[i],i});
    for (int i=0;i<l.size();i++)
        if (l[i]<s&&s<r[i]){
            auto a=tmp[lower_bound(tmp.begin(),tmp.end(),make_pair(y[i],-1))-tmp.begin()];
            changes.push_back({i,a.second});
        }
    for (auto [i,j]:changes){
        if (j==l[i]||j==r[i])
            continue;
        if (mode)
            swap(l,r);
        l.push_back(j);
        r.push_back(r[i]);
        y.push_back(y[i]);
        r[i]=j;
        if (mode)
            swap(l,r);
    }
}
int min_distance(vector<int32_t> X, vector<int32_t> H, vector<int32_t> L, vector<int32_t> R, vector<int32_t> Y, int32_t s, int32_t g){
    x=X,h=H,l=L,r=R,y=Y,n=x.size();
    if (s>g)
        swap(s,g);
    reconnect(s,0);
    reconnect(s,1);
    reconnect(g,0);
    reconnect(g,1);
    m=l.size();
    for (int i=0;i<m;i++){
        ve.push_back({l[i],i});
        ve.push_back({r[i],i});
    }
    sort(ve.begin(),ve.end(),[](pair <int, int> a, pair <int, int> b){
            if (a.first!=b.first)
                return a.first<b.first;
            bool p=(a.first==r[a.second]),q=(b.first==r[b.second]);
            if (p!=q)
                return p<q;
            if (p)
                return y[a.second]>y[b.second];
            return y[a.second]<y[b.second];
         });
    set <pair <int, int>> cur;
    for (auto [i,j]:ve){
        add(i,j);
        b[j].push_back(i);
        if (i==l[j])
            cur.insert({y[j],j});
        else
            cur.erase({y[j],j});
        if (!cur.empty()){
            auto it=cur.lower_bound(make_pair(y[j],-1));
            if (it!=cur.begin()){
                it--;
                add(i,(*it).second);
                b[(*it).second].push_back(i);
            }
        }
    }
    for (int i=0;i<n;i++)
        sort(a[i].begin(),a[i].end(),[](int i, int j){return y[i]>y[j];});
    for (int i=0;i<m;i++)
        sort(b[i].begin(),b[i].end(),[](int i, int j){return x[i]<x[j];});
    add(s,-1);
    add(g,-1);
    sort(nodes.begin(),nodes.end());
    nodes.resize(unique(nodes.begin(),nodes.end())-nodes.begin());
    for (int i=0;i<n;i++)
        for (int j=0;j<(int)a[i].size()-1;j++){
            int u=f(i,a[i][j]),v=f(i,a[i][j+1]),w=(a[i][j]>=0?y[a[i][j]]:0)-(a[i][j+1]>=0?y[a[i][j+1]]:0);
            if (u==v)
                continue;
            ke[u].push_back({v,w});
            ke[v].push_back({u,w});
        }
    for (int i=0;i<m;i++)
        for (int j=0;j<(int)b[i].size()-1;j++){
            int u=f(b[i][j],i),v=f(b[i][j+1],i),w=x[b[i][j+1]]-x[b[i][j]];
            if (u==v)
                continue;
            ke[u].push_back({v,w});
            ke[v].push_back({u,w});
        }
    fill(d,d+nodes.size(),INF);
    d[f(s,-1)]=0;
    q.push({0,f(s,-1)});
    while (!q.empty()){
        auto [du,u]=q.top();
        q.pop();
        if (du!=d[u])
            continue;
        for (auto [v,w]:ke[u])
            if (d[v]>d[u]+w){
                d[v]=d[u]+w;
                q.push({d[v],v});
            }
    }
    return (d[f(g,-1)]==INF?-1:d[f(g,-1)]);
}

Compilation message (stderr)

walk.cpp: In function 'void reconnect(int32_t, long long int)':
walk.cpp:25:19: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |     for (int i=0;i<l.size();i++)
      |                  ~^~~~~~~~~

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