#include <bits/stdc++.h>
using namespace std;
#define pii pair <int, int>
#define fi first
#define se second
#define mp make_pair
#define getbit(x, i) ((x&(1<<i)) != 0)
const int NM = 1000;
int N, S, a[NM+5];
vector <pii> ans;
void op(int i, int j){
ans.push_back(mp(i, j));
a[i] ^= a[j];
}
void solve1(){
for (int i = N; i >= 1; i--){
int k = 1;
for (int j = 2; j <= i; j++)
if (a[j] > a[k]) k = j;
int cur = a[i];
bool ok = 0;
for (int j = i+1; j <= N; j++){
cur ^= a[j];
if (cur < a[i+1] && cur >= a[k]){
ok = 1;
for (int ii = j-1; ii >= i; ii--)
op(ii, ii+1);
for (int ii = i+1; ii < j; ii++)
op(ii, ii+1);
break;
}
}
if (ok) continue;
for (int j = 1; j < i; j++)
if (a[j] > a[j+1]){
op(j+1, j);
op(j, j+1);
op(j+1, j);
}
}
}
void solve2(){
int tar = N+1;
for (int i = 19; i >= 0; i--){
bool ok = 0;
for (int j = 1; j <= N; j++)
if (getbit(a[j], i)){
ok = 1;
break;
}
if (ok == 0) continue;
tar--;
for (int j = 1; j < tar; j++)
if (getbit(a[j], i) && !getbit(a[j+1], i)){
op(j+1, j);
op(j, j+1);
}
else if (getbit(a[j], i) && getbit(a[j+1], i)){
op(j, j+1);
}
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> N >> S;
for (int i = 1; i <= N; i++) cin >> a[i];
if (S == 1) solve1();
else solve2();
cout << ans.size() << '\n';
for (int i = 0; i < ans.size(); i++)
cout << ans[i].fi << ' ' << ans[i].se << '\n';
return 0;
}
Compilation message
xorsort.cpp: In function 'int main()':
xorsort.cpp:79:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
79 | for (int i = 0; i < ans.size(); i++)
| ~~^~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
212 KB |
Output is correct |
| 2 |
Correct |
0 ms |
212 KB |
Output is correct |
| 3 |
Correct |
1 ms |
340 KB |
Output is correct |
| 4 |
Correct |
2 ms |
600 KB |
Output is correct |
| 5 |
Correct |
2 ms |
728 KB |
Output is correct |
| 6 |
Correct |
2 ms |
724 KB |
Output is correct |
| 7 |
Correct |
4 ms |
600 KB |
Output is correct |
| 8 |
Correct |
3 ms |
728 KB |
Output is correct |
| 9 |
Correct |
3 ms |
728 KB |
Output is correct |
| 10 |
Correct |
2 ms |
600 KB |
Output is correct |
| 11 |
Correct |
1 ms |
340 KB |
Output is correct |
| 12 |
Correct |
3 ms |
856 KB |
Output is correct |
| 13 |
Correct |
4 ms |
856 KB |
Output is correct |
| 14 |
Correct |
3 ms |
828 KB |
Output is correct |
| 15 |
Correct |
4 ms |
728 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
212 KB |
Output is correct |
| 2 |
Correct |
0 ms |
212 KB |
Output is correct |
| 3 |
Correct |
1 ms |
340 KB |
Output is correct |
| 4 |
Correct |
2 ms |
600 KB |
Output is correct |
| 5 |
Correct |
2 ms |
728 KB |
Output is correct |
| 6 |
Correct |
2 ms |
724 KB |
Output is correct |
| 7 |
Correct |
4 ms |
600 KB |
Output is correct |
| 8 |
Correct |
3 ms |
728 KB |
Output is correct |
| 9 |
Correct |
3 ms |
728 KB |
Output is correct |
| 10 |
Correct |
2 ms |
600 KB |
Output is correct |
| 11 |
Correct |
1 ms |
340 KB |
Output is correct |
| 12 |
Correct |
3 ms |
856 KB |
Output is correct |
| 13 |
Correct |
4 ms |
856 KB |
Output is correct |
| 14 |
Correct |
3 ms |
828 KB |
Output is correct |
| 15 |
Correct |
4 ms |
728 KB |
Output is correct |
| 16 |
Correct |
0 ms |
212 KB |
Output is correct |
| 17 |
Correct |
3 ms |
728 KB |
Output is correct |
| 18 |
Correct |
4 ms |
888 KB |
Output is correct |
| 19 |
Correct |
4 ms |
856 KB |
Output is correct |
| 20 |
Correct |
4 ms |
856 KB |
Output is correct |
| 21 |
Correct |
7 ms |
856 KB |
Output is correct |
| 22 |
Correct |
4 ms |
984 KB |
Output is correct |
| 23 |
Correct |
4 ms |
856 KB |
Output is correct |
| 24 |
Correct |
4 ms |
856 KB |
Output is correct |
| 25 |
Correct |
4 ms |
904 KB |
Output is correct |
| 26 |
Incorrect |
6 ms |
1196 KB |
Integer 51788 violates the range [0, 40000] |
| 27 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
212 KB |
Output is correct |
| 2 |
Correct |
0 ms |
212 KB |
Output is correct |
| 3 |
Correct |
1 ms |
340 KB |
Output is correct |
| 4 |
Correct |
1 ms |
468 KB |
Output is correct |
| 5 |
Correct |
6 ms |
856 KB |
Output is correct |
| 6 |
Correct |
4 ms |
856 KB |
Output is correct |
| 7 |
Correct |
4 ms |
856 KB |
Output is correct |
| 8 |
Correct |
5 ms |
856 KB |
Output is correct |
| 9 |
Correct |
4 ms |
856 KB |
Output is correct |
| 10 |
Correct |
6 ms |
856 KB |
Output is correct |
| 11 |
Correct |
4 ms |
856 KB |
Output is correct |
| 12 |
Correct |
4 ms |
856 KB |
Output is correct |
| 13 |
Correct |
4 ms |
956 KB |
Output is correct |
| 14 |
Correct |
4 ms |
856 KB |
Output is correct |
| 15 |
Correct |
5 ms |
980 KB |
Output is correct |
