I was trying to submit this -> Remove Max Number of Edges to Keep Graph Fully Traversable question.

but I got TLE because of sort using rbegin

sort( edges.rbegin(), edges.rend())

but after change with comparator funtction code got accepted.

sort(edges.begin(), edges.end(), [&](vector <int> &a, vector <int> &b){
            return a[0] > b[0];
        });

Submission Using rbegin Submission Using comparator

I tried to run this in local and got similar perfomance but when I used some different build command I got 2x tiime difference.

Build command:

g++ a.cpp

g++ -std=c++17 -Wshadow -Wall -fsanitize=address -fsanitize=undefined -D_GLIBCXX_DEBUG -DLOCAL a.cpp

Following code I used for benchmarking.

Benchmarking code

int n;
cin >> n;
srand(time(0)); 
vector <int> ans(n);

for(int i = 0; i < n; ++i){
	ans[i] = random() % 100000;
}



vector <int> xyz = ans;

const clock_t begin_time = clock();

sort(ans.begin(), ans.end(), greater <int> ());

std::cout << float( clock () - begin_time ) /  CLOCKS_PER_SEC << endl;

const clock_t begin_time2 = clock();
sort(xyz.rbegin(), xyz.rend());

std::cout << float( clock () - begin_time2 ) /  CLOCKS_PER_SEC << endl;

I think that leetcode is using similar build command to execute the program. Can anyone explain why this time difference happening?