Submission #492942

#	Time	Username	Problem	Language	Result	Execution time	Memory
492942		kevin	Roller Coaster Railroad (IOI16_railroad)	C++17	0 / 100	294 ms	31884 KiB

railroad

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define all(x) x.begin(), x.end()
#define f first
#define s second
#define ca(v) for(auto i:v) cout<<i<<" ";
#define nl cout<<"\n"

const int MAXN = 5e5 + 5;

ll plan_roller_coaster(vector<int> s, vector<int> t){
    int N = s.size();
    unordered_map<int, int> hsh;
    vector<int> cmp;
    for(int i=0; i<N; i++) { 
        cmp.push_back(s[i]);
        cmp.push_back(t[i]);
    }
    cmp.push_back(0);
    sort(all(cmp));
    cmp.resize(unique(all(cmp)) - cmp.begin());
    for(int i=0; i<cmp.size(); i++) hsh[cmp[i]] = i;
    vector<int> in(cmp.size(), 0);
    vector<int> out(cmp.size(), 0);
    // update all the outs
    for(int i=0; i<N; i++) out[hsh[s[i]]]++;
    // greedily assign right arrows
    vector<int> rgt;
    for(int i=0; i<N; i++) rgt.push_back(hsh[t[i]]);
    rgt.push_back(0);
    sort(all(rgt));
    int p = 1;
    for(int i:rgt){
        while(p<cmp.size() && (p < i || out[p] == in[p])) p++;
        if(p<cmp.size()){
            in[p]++;
        }
    }
    for(int i=1; i<cmp.size(); i++){
        if(out[i] > in[i]) return 1;
    }
    return 0;
}

Compilation message (stderr)

railroad.cpp: In function 'long long int plan_roller_coaster(std::vector<int>, std::vector<int>)':
railroad.cpp:24:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |     for(int i=0; i<cmp.size(); i++) hsh[cmp[i]] = i;
      |                  ~^~~~~~~~~~~
railroad.cpp:36:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |         while(p<cmp.size() && (p < i || out[p] == in[p])) p++;
      |               ~^~~~~~~~~~~
railroad.cpp:37:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   37 |         if(p<cmp.size()){
      |            ~^~~~~~~~~~~
railroad.cpp:41:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |     for(int i=1; i<cmp.size(); i++){
      |                  ~^~~~~~~~~~~

• Subtask 1: 0 / 11
• Subtask 2: 0 / 23
• Subtask 3: 0 / 30
• Subtask 4: 0 / 36