//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
}
int N,S[MX],X[MX],Y[MX];
vi plate(MX),pos(MX),cur(MX),final(MX),apple(MX);
vpi vec;
bool check(int n){
vec.clear();
//initialize containers
FOR(i,0,N){
plate[i]=i;
pos[i]=i;
apple[i]=S[i];
cur[apple[i]]=i;
}
vi v(N); FOR(i,0,N) v[i]=i;
FOR(i,0,n) swap(v[X[i]],v[Y[i]]);
FOR(i,0,N) final[i]=v[i];
//FOR(i,0,N) cout << final[i] << ' '; cout << endl;
//compute
int cnt=0; //nb of operations needed
FOR(i,0,N) if(final[i]!=cur[i]){
//First plays
int l=X[cnt],r=Y[cnt];
//dbgs(l,r)
swap(plate[l],plate[r]);
swap(pos[plate[l]],pos[plate[r]]);
//Sec plays
vec.eb(pos[cur[i]],pos[final[i]]);
int app=apple[final[i]];
swap(apple[cur[i]],apple[final[i]]);
swap(cur[i],cur[app]);
assert(cur[i]==final[i]);
cnt++;
}
if(cnt>n) return false;
FOR(i,cnt,n) vec.eb(0,0);
return true;
}
int findSwapPairs(int N, int s[], int M, int x[], int y[], int P[], int Q[]){
::N=N;
FOR(i,0,N) S[i]=s[i];
FOR(i,0,N) X[i]=x[i],Y[i]=y[i];
int l=0,r=N-1;
vpi ans;
while(l<=r){
int m=(l+r)/2;
if(check(m)){
r=m-1;
ans.assign(all(vec));
}
else l=m+1;
}
FOR(i,0,sz(ans)){
P[i]=ans[i].fi,Q[i]=ans[i].se;
swap(s[x[i]],s[y[i]]);
swap(s[P[i]],s[Q[i]]);
}
//FOR(i,0,N) cout << s[i] << ' '; cout << endl;
return sz(ans);
}
#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);
//FOR(i,0,N) cout << s[i] << ' '; cout << endl;
int M=3*N;
int p[M],q[M],x[M],y[M];
FOR(i,0,M) x[i]=random(0,N-1),y[i]=random(0,N-1);
//FOR(i,0,M) cout << x[i] << ' ' << y[i] << endl;
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:110:76: warning: declaration of 'N' shadows a global declaration [-Wshadow]
110 | int findSwapPairs(int N, int s[], int M, int x[], int y[], int P[], int Q[]){
| ^
sorting.cpp:68:5: note: shadowed declaration is here
68 | int N,S[MX],X[MX],Y[MX];
| ^
sorting.cpp:110:39: warning: unused parameter 'M' [-Wunused-parameter]
110 | int findSwapPairs(int N, int s[], int M, int x[], int y[], int P[], int Q[]){
| ~~~~^
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
4204 KB |
Output is correct |
2 |
Correct |
3 ms |
4204 KB |
Output is correct |
3 |
Correct |
4 ms |
4204 KB |
Output is correct |
4 |
Correct |
4 ms |
4204 KB |
Output is correct |
5 |
Correct |
4 ms |
4320 KB |
Output is correct |
6 |
Correct |
4 ms |
4204 KB |
Output is correct |
7 |
Correct |
4 ms |
4204 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
4204 KB |
Output is correct |
2 |
Correct |
3 ms |
4204 KB |
Output is correct |
3 |
Correct |
4 ms |
4204 KB |
Output is correct |
4 |
Correct |
4 ms |
4204 KB |
Output is correct |
5 |
Correct |
4 ms |
4320 KB |
Output is correct |
6 |
Correct |
4 ms |
4204 KB |
Output is correct |
7 |
Correct |
4 ms |
4204 KB |
Output is correct |
8 |
Correct |
5 ms |
4204 KB |
Output is correct |
9 |
Correct |
4 ms |
4204 KB |
Output is correct |
10 |
Correct |
4 ms |
4332 KB |
Output is correct |
11 |
Correct |
4 ms |
4332 KB |
Output is correct |
12 |
Correct |
4 ms |
4204 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
4204 KB |
Output is correct |
2 |
Correct |
4 ms |
4352 KB |
Output is correct |
3 |
Correct |
5 ms |
4332 KB |
Output is correct |
4 |
Correct |
5 ms |
4332 KB |
Output is correct |
5 |
Correct |
4 ms |
4332 KB |
Output is correct |
6 |
Correct |
4 ms |
4204 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
4204 KB |
Output is correct |
2 |
Correct |
3 ms |
4204 KB |
Output is correct |
3 |
Correct |
4 ms |
4204 KB |
Output is correct |
4 |
Correct |
4 ms |
4204 KB |
Output is correct |
5 |
Correct |
4 ms |
4320 KB |
Output is correct |
6 |
Correct |
4 ms |
4204 KB |
Output is correct |
7 |
Correct |
4 ms |
4204 KB |
Output is correct |
8 |
Correct |
5 ms |
4204 KB |
Output is correct |
9 |
Correct |
4 ms |
4204 KB |
Output is correct |
10 |
Correct |
4 ms |
4332 KB |
Output is correct |
11 |
Correct |
4 ms |
4332 KB |
Output is correct |
12 |
Correct |
4 ms |
4204 KB |
Output is correct |
13 |
Correct |
4 ms |
4204 KB |
Output is correct |
14 |
Correct |
4 ms |
4352 KB |
Output is correct |
15 |
Correct |
5 ms |
4332 KB |
Output is correct |
16 |
Correct |
5 ms |
4332 KB |
Output is correct |
17 |
Correct |
4 ms |
4332 KB |
Output is correct |
18 |
Correct |
4 ms |
4204 KB |
Output is correct |
19 |
Correct |
4 ms |
4204 KB |
Output is correct |
20 |
Correct |
4 ms |
4204 KB |
Output is correct |
21 |
Correct |
4 ms |
4460 KB |
Output is correct |
22 |
Correct |
4 ms |
4460 KB |
Output is correct |
23 |
Correct |
4 ms |
4460 KB |
Output is correct |
24 |
Correct |
4 ms |
4460 KB |
Output is correct |
25 |
Correct |
4 ms |
4460 KB |
Output is correct |
26 |
Correct |
4 ms |
4492 KB |
Output is correct |
27 |
Correct |
5 ms |
4460 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
4460 KB |
Output is correct |
2 |
Correct |
5 ms |
4460 KB |
Output is correct |
3 |
Correct |
5 ms |
4460 KB |
Output is correct |
4 |
Correct |
4 ms |
4460 KB |
Output is correct |
5 |
Correct |
4 ms |
4460 KB |
Output is correct |
6 |
Correct |
5 ms |
4460 KB |
Output is correct |
7 |
Correct |
6 ms |
4460 KB |
Output is correct |
8 |
Correct |
6 ms |
4460 KB |
Output is correct |
9 |
Correct |
7 ms |
4460 KB |
Output is correct |
10 |
Correct |
5 ms |
4460 KB |
Output is correct |
11 |
Correct |
6 ms |
4460 KB |
Output is correct |
12 |
Correct |
5 ms |
4460 KB |
Output is correct |
13 |
Correct |
7 ms |
4460 KB |
Output is correct |
14 |
Correct |
5 ms |
4460 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
4460 KB |
Output is correct |
2 |
Correct |
5 ms |
4460 KB |
Output is correct |
3 |
Correct |
5 ms |
4460 KB |
Output is correct |
4 |
Correct |
4 ms |
4460 KB |
Output is correct |
5 |
Correct |
4 ms |
4460 KB |
Output is correct |
6 |
Correct |
5 ms |
4460 KB |
Output is correct |
7 |
Correct |
6 ms |
4460 KB |
Output is correct |
8 |
Correct |
6 ms |
4460 KB |
Output is correct |
9 |
Correct |
7 ms |
4460 KB |
Output is correct |
10 |
Correct |
5 ms |
4460 KB |
Output is correct |
11 |
Correct |
6 ms |
4460 KB |
Output is correct |
12 |
Correct |
5 ms |
4460 KB |
Output is correct |
13 |
Correct |
7 ms |
4460 KB |
Output is correct |
14 |
Correct |
5 ms |
4460 KB |
Output is correct |
15 |
Correct |
198 ms |
17216 KB |
Output is correct |
16 |
Correct |
227 ms |
25100 KB |
Output is correct |
17 |
Correct |
336 ms |
26268 KB |
Output is correct |
18 |
Correct |
88 ms |
21904 KB |
Output is correct |
19 |
Correct |
226 ms |
23524 KB |
Output is correct |
20 |
Correct |
242 ms |
25176 KB |
Output is correct |
21 |
Correct |
244 ms |
25144 KB |
Output is correct |
22 |
Correct |
196 ms |
21632 KB |
Output is correct |
23 |
Correct |
224 ms |
27348 KB |
Output is correct |
24 |
Correct |
350 ms |
26788 KB |
Output is correct |
25 |
Correct |
324 ms |
26512 KB |
Output is correct |
26 |
Correct |
222 ms |
25804 KB |
Output is correct |
27 |
Correct |
205 ms |
23776 KB |
Output is correct |
28 |
Correct |
268 ms |
26648 KB |
Output is correct |
29 |
Correct |
303 ms |
25920 KB |
Output is correct |
30 |
Correct |
154 ms |
23388 KB |
Output is correct |
31 |
Correct |
296 ms |
26624 KB |
Output is correct |
32 |
Correct |
225 ms |
26388 KB |
Output is correct |
33 |
Correct |
360 ms |
26872 KB |
Output is correct |
34 |
Correct |
243 ms |
26752 KB |
Output is correct |
35 |
Correct |
219 ms |
23232 KB |
Output is correct |
36 |
Correct |
75 ms |
23000 KB |
Output is correct |
37 |
Correct |
346 ms |
27720 KB |
Output is correct |
38 |
Correct |
331 ms |
26512 KB |
Output is correct |
39 |
Correct |
345 ms |
26752 KB |
Output is correct |