Submission #645647

#	Time	Username	Problem	Language	Result	Execution time	Memory
645647		czhang2718	Permutation (APIO22_perm)	C++17	0 / 100	1 ms	212 KiB

perm

#include "bits/stdc++.h"
using namespace std;
 
// #include "perm.h"
 
std::vector<int> construct_permutation(long long S)
{
    vector<int> v;
    bool emp=1;
    for(int i=30; i>=0; i--){
        int d=(S/(1LL<<(2*i)))%4;
        if(emp){
            if(!d) continue;
            if(d==1) {}
            if(d==2) v={0};
            if(d==3) v={1,0};
            emp=0;
            continue;
        }
        if(d==0){
            int mx=(v.size()?*max_element(v.begin(), v.end()):0);
            v.push_back(mx+1);
            v.push_back(mx+2);
        }
        if(d==1){
            int mx=(v.size()?*max_element(v.begin(), v.end()):0);
            v.push_back(mx+1);
            v.push_back(mx+2);
            int mn=(v.size()?*min_element(v.begin(), v.end()):0);
            v.push_back(mn-1);
        }
        if(d==2){
            int mx=(v.size()?*max_element(v.begin(), v.end()):0);
            v.push_back(mx+1);
            int mn=(v.size()?*min_element(v.begin(), v.end()):0);
            v.push_back(mn-1);
            v.push_back(mx+2);
        }
        if(d==3){
            if(!v.size()) v={2, 1, 0};
            else{
                int mx=(v.size()?*max_element(v.begin(), v.end()):0);
                v.push_back(mx+1);
                v.push_back(mx+2);
                int mn=(v.size()?*min_element(v.begin(), v.end()):0);
                int i0,i1;
                for(int j=0; j<v.size(); j++){
                    if(v[j]==mn) i0=j;
                    if(v[j]==mn+1) i1=j;
                }
                if(i1<i0){
                    v[i0]--, v[i1]--;
                    v.push_back(mn+1);
                }
                else{
                    v.push_back(mn-2);
                    v.push_back(mn-1);
                }
            }
        }
    }
    vector<int> a=v;
    sort(a.begin(), a.end());
    for(int &x:v) x=lower_bound(a.begin(), a.end(), x)-a.begin();
    return v;
}
 
 
// int main(){
//     cin.tie(0)->sync_with_stdio(0);
 
//     int k; cin >> k;
//     for(int x:construct_permutation(k)) cout << x << " ";
// }

Compilation message (stderr)

perm.cpp: In function 'std::vector<int> construct_permutation(long long int)':
perm.cpp:47:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   47 |                 for(int j=0; j<v.size(); j++){
      |                              ~^~~~~~~~~
perm.cpp:52:34: warning: 'i1' may be used uninitialized in this function [-Wmaybe-uninitialized]
   52 |                     v[i0]--, v[i1]--;
      |                                  ^
perm.cpp:52:25: warning: 'i0' may be used uninitialized in this function [-Wmaybe-uninitialized]
   52 |                     v[i0]--, v[i1]--;
      |                         ^

• Subtask 1: 0 / 10
• Subtask 2: 0 / 90