#include <bits/stdc++.h>
#include "railroad.h"
using namespace std;
int n;
deque <pair <int,int> > EnterSpeed;
deque <pair <int,int> > ExitSpeed;
long long plan_roller_coaster (vector <int> s, vector <int> t){
n=s.size();
/*
Subtask 1 and 2 is trival and basically not worth spending time for, so I'll skip it
Of course, there exists a better solution to subtask 3 that is actually relevant to the full solution, but 30 points is 30 points,
especially if that's from a shitty greedy solution
*/
/*
If a finished track could be created without adding in any additional segments, this is the equivalent of: for all but 1 segment, there
has to be a track segment that follows it.
=> Just greedily assign exit speeds with corresponding entrance speeds that isn't from the same segment,
if n-1 pairs (or more) could be formed, there exists an answer.
Simple as that.
*/
for(int i=0;i<n;i++){
EnterSpeed.push_back({s[i],i});
ExitSpeed.push_back({t[i],i});
}
sort(EnterSpeed.begin(),EnterSpeed.end());
sort(ExitSpeed.begin(),ExitSpeed.end());
int ValidPairs=0;
pair <int,int> temp;
//Assigning track endpoints with new tracks
while(!EnterSpeed.empty()){
//Trying to match with the startpoint that isn't in the same track, and has the smallest entrance speed possible
while(!EnterSpeed.empty()&&ExitSpeed.front().first>EnterSpeed.front().first){
EnterSpeed.pop_front();
}
//It matches and doesn't belong to the same sector. Is valid, so increase the amount of matched pairs by 1
if(!EnterSpeed.empty()&&ExitSpeed.front().second!=EnterSpeed.front().second){
ValidPairs++;
EnterSpeed.pop_front();
ExitSpeed.pop_front();
}else if(!EnterSpeed.size()>1){
//It matches, but both of this startpoint and endpoint belongs in the same segment. Match it with the
//next smallest unmatched entrance speed
temp=EnterSpeed.front();
EnterSpeed.pop_front();
ValidPairs++;
EnterSpeed.push_front(temp);
}
}
//If at least N-1 pairs could be matched, there exists 1 valid rollercoaster using only the default tracks. Otherwise, no
return (ValidPairs>=n-1);
}
Compilation message
railroad.cpp: In function 'long long int plan_roller_coaster(std::vector<int>, std::vector<int>)':
railroad.cpp:41:30: warning: logical not is only applied to the left hand side of comparison [-Wlogical-not-parentheses]
41 | }else if(!EnterSpeed.size()>1){
| ^
railroad.cpp:41:12: note: add parentheses around left hand side expression to silence this warning
41 | }else if(!EnterSpeed.size()>1){
| ^~~~~~~~~~~~~~~~~~
| ( )
railroad.cpp:41:30: warning: comparison of constant '1' with boolean expression is always false [-Wbool-compare]
41 | }else if(!EnterSpeed.size()>1){
| ~~~~~~~~~~~~~~~~~~^~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
2063 ms |
348 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
2063 ms |
348 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
2012 ms |
10724 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
2063 ms |
348 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
