//Never stop trying
/*#pragma GCC target ("avx2")
#pragma GCC optimize ("Ofast")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")*/
#include "bits/stdc++.h"
#ifndef LOCAL
#include "sorting.h"
#endif
using namespace std;
#define boost ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
typedef long long ll;
typedef string str;
typedef double db;
typedef long double ld;
typedef pair<int, int> pi;
#define fi first
#define se second
typedef vector<int> vi;
typedef vector<pi> vpi;
typedef vector<str> vs;
typedef vector<ld> vd;
#define pb push_back
#define eb emplace_back
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define endl "\n"
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
const int MOD = 1e9 + 7; //998244353
const ll INF = 1e18;
const int MX = 2e5 + 10;
const int nx[4] = {0, 0, 1, -1}, ny[4] = {1, -1, 0, 0}; //right left down up
template<class T> using V = vector<T>;
template<class T> bool ckmin(T& a, const T& b) { return a > b ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); } // divide a by b rounded up
//constexpr int log2(int x) { return 31 - __builtin_clz(x); } // floor(log2(x))
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
//mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
ll random(ll a, ll b){
return a + rng() % (b - a + 1);
}
#ifndef LOCAL
#define cerr if(false) cerr
#endif
#define dbg(x) cerr << #x << " : " << x << endl;
#define dbgs(x,y) cerr << #x << " : " << x << " / " << #y << " : " << y << endl;
#define dbgv(v) cerr << #v << " : " << "[ "; for(auto it : v) cerr << it << ' '; cerr << ']' << endl;
#define here() cerr << "here" << endl;
void IO() {
#ifdef LOCAL
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
}
vpi vec;
vi solve(vi v, int l, int r){
if(sz(v)==1) return v;
vi a,b;
int N=sz(v);
int m=N/2;
FOR(i,0,m) a.pb(v[i]);
FOR(i,m,N) b.pb(v[i]);
a=solve(a,l,l+m-1);
b=solve(b,l+m,r);
v.clear();
for(auto x: a) v.pb(x);
for(auto x: b) v.pb(x);
vi vv; vv.assign(all(v));
sort(all(vv));
FOR(i,0,N){
int idx=-1;
FOR(j,0,N) if(vv[i]==v[j]) idx=j;
swap(v[i],v[idx]);
vec.eb(i+l,idx+l);
}
return v;
}
bool check(int s[], int N){
FOR(i,0,N) if(s[i]!=i) return 0;
return 1;
}
int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
vi v;
bool y=true;
FOR(i,0,N){
v.pb(S[i]);
if(S[i]!=i) y=false;
}
if(y) return 0;
vec.clear();
v=solve(v,0,N-1);
if(vec.empty()) vec.eb(0,0);
int cnt=0;
FOR(i,0,sz(vec)){
P[i]=vec[i].fi,Q[i]=vec[i].se;
swap(S[Q[i]],S[P[i]]);
cnt++;
if(check(S,N)) break;
}
assert(sz(vec)<=M);
return cnt;
}
#ifdef LOCAL
int main() {
boost; IO();
int N; cin>>N;
int s[N]; FOR(i,0,N) s[i]=i;
random_shuffle(s,s+N);
int M=N*30;
int p[M],q[M],x[M],y[M];
FOR(i,0,M) x[i]=y[i]=0;
cout << findSwapPairs(N,s,M,x,y,p,q) << endl;
return 0;
}
#endif
/* Careful!!!
.Array bounds
.Infinite loops
.Uninitialized variables / empty containers
.Multisets are shit
Some insights:
.Binary search
.Graph representation
.Write brute force code
.Change your approach
*/
Compilation message
sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:100:46: warning: unused parameter 'X' [-Wunused-parameter]
100 | int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
| ~~~~^~~
sorting.cpp:100:55: warning: unused parameter 'Y' [-Wunused-parameter]
100 | int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
| ~~~~^~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
364 KB |
Output is correct |
| 2 |
Correct |
1 ms |
364 KB |
Output is correct |
| 3 |
Correct |
0 ms |
364 KB |
Output is correct |
| 4 |
Incorrect |
1 ms |
364 KB |
Output isn't correct |
| 5 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
364 KB |
Output is correct |
| 2 |
Correct |
1 ms |
364 KB |
Output is correct |
| 3 |
Correct |
0 ms |
364 KB |
Output is correct |
| 4 |
Incorrect |
1 ms |
364 KB |
Output isn't correct |
| 5 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
364 KB |
Output is correct |
| 2 |
Incorrect |
1 ms |
364 KB |
Output isn't correct |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
364 KB |
Output is correct |
| 2 |
Correct |
1 ms |
364 KB |
Output is correct |
| 3 |
Correct |
0 ms |
364 KB |
Output is correct |
| 4 |
Incorrect |
1 ms |
364 KB |
Output isn't correct |
| 5 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
8 ms |
1264 KB |
Execution killed with signal 6 (could be triggered by violating memory limits) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
8 ms |
1264 KB |
Execution killed with signal 6 (could be triggered by violating memory limits) |
| 2 |
Halted |
0 ms |
0 KB |
- |
