Submission #874666

#	Time	Username	Problem	Language	Result	Execution time	Memory
874666		abcvuitunggio	Roller Coaster Railroad (IOI16_railroad)	C++17	100 / 100	194 ms	28996 KiB

railroad

#include "railroad.h"
#include <bits/stdc++.h>
#define int long long
using namespace std;
int sum[500001],p[500001];
int f(int i){
    return (p[i]==i?i:p[i]=f(p[i]));
}
int unite(int i, int j){
    i=f(i);
    j=f(j);
    if (i==j)
        return 0;
    p[j]=i;
    return 1;
}
long long plan_roller_coaster(vector <int32_t> s, vector <int32_t> t){
    int n=s.size();
    vector <int> ve;
    vector <pair <int, int>> ve2;
    for (int i=0;i<n;i++){
        ve.push_back(s[i]);
        ve.push_back(t[i]);
    }
    sort(ve.begin(),ve.end());
    ve.resize(unique(ve.begin(),ve.end())-ve.begin());
    int res=0;
    iota(p,p+ve.size()+2,0);
    for (int i=0;i<n;i++){
        s[i]=lower_bound(ve.begin(),ve.end(),s[i])-ve.begin()+1;
        t[i]=lower_bound(ve.begin(),ve.end(),t[i])-ve.begin()+1;
        sum[s[i]]++;
        sum[t[i]]--;
        unite(s[i],t[i]);
    }
    sum[1]--;
    unite(1,ve.size()+1);
    for (int i=1;i<=ve.size();i++){
        sum[i]+=sum[i-1];
        if (sum[i])
            unite(i,i+1);
        if (i<ve.size()){
            res+=max(sum[i]*(ve[i]-ve[i-1]),0LL);
            ve2.push_back({ve[i]-ve[i-1],i});
        }
    }
    sort(ve2.begin(),ve2.end());
    for (auto [w,i]:ve2)
        res+=w*unite(i,i+1);
    return res;
}

Compilation message (stderr)

railroad.cpp: In function 'long long int plan_roller_coaster(std::vector<int>, std::vector<int>)':
railroad.cpp:38:19: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |     for (int i=1;i<=ve.size();i++){
      |                  ~^~~~~~~~~~~
railroad.cpp:42:14: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |         if (i<ve.size()){
      |             ~^~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 23 / 23
• Subtask 3: 30 / 30
• Subtask 4: 36 / 36