#include "sorting.h"
#include <bits/stdc++.h>
#define MAXN 200015
using namespace std;
int bk[MAXN],pos_bk[MAXN],pre[MAXN],pos_pre[MAXN];
int solve(int N,int n,int S[],int P[],int Q[],int X[],int Y[]){
int now=0,cnt_same=0;
for (int i=0;i<N;i++){
bk[i]=i; pos_bk[i]=i;
pre[i]=S[i]; pos_pre[S[i]]=i;
if (pre[i]==i) cnt_same++;
}
for (int i=n-1;i>=0;i--){
swap(bk[X[i]],bk[Y[i]]);
pos_bk[bk[X[i]]]=X[i];
pos_bk[bk[Y[i]]]=Y[i];
}
for (int i=0;i<n;i++){
if (cnt_same==N) return i;
if (pre[X[i]]==X[i]) cnt_same--;
if (pre[Y[i]]==Y[i]) cnt_same--;
swap(pre[X[i]],pre[Y[i]]);
if (pre[X[i]]==X[i]) cnt_same++;
if (pre[Y[i]]==Y[i]) cnt_same++;
pos_pre[pre[X[i]]]=X[i];
pos_pre[pre[Y[i]]]=Y[i];
swap(bk[X[i]],bk[Y[i]]);
pos_bk[bk[X[i]]]=X[i];
pos_bk[bk[Y[i]]]=Y[i];
now=i;
while (now<N&&pos_pre[now]==pos_bk[now])
now++;
if (now>=N) continue;
P[i]=pos_pre[now]; Q[i]=pos_bk[now];
if (pre[P[i]]==P[i]) cnt_same--;
if (pre[Q[i]]==Q[i]) cnt_same--;
swap(pre[pos_pre[now]],pre[pos_bk[now]]);
if (pre[P[i]]==P[i]) cnt_same++;
if (pre[Q[i]]==Q[i]) cnt_same++;
pos_pre[pre[pos_pre[now]]]=pos_pre[now];
pos_pre[pre[pos_bk[now]]]=pos_bk[now];
}
bool flag=1;
for (int i=0;i<N;i++){
if (pre[i]!=i) flag=0;
}
if (flag) return n;
else return 1e9;
}
int solve1(int N,int n,int S[],int P[],int Q[],int X[],int Y[]){
for (int i=0;i<N;i++){
bk[i]=i; pos_bk[i]=i;
pre[i]=S[i]; pos_pre[S[i]]=i;
}
for (int i=n-1;i>=0;i--){
swap(bk[X[i]],bk[Y[i]]);
pos_bk[bk[X[i]]]=X[i];
pos_bk[bk[Y[i]]]=Y[i];
}
int now=0;
for (int i=0;i<n;i++){
bool flag=1;
for (int j=0;j<N;j++){
if (pre[j]!=j){
flag=0;
break;
}
}
if (flag)
return i;
swap(pre[X[i]],pre[Y[i]]);
pos_pre[pre[X[i]]]=X[i];
pos_pre[pre[Y[i]]]=Y[i];
swap(bk[X[i]],bk[Y[i]]);
pos_bk[bk[X[i]]]=X[i];
pos_bk[bk[Y[i]]]=Y[i];
now=i;
while (now<N&&pos_pre[now]==pos_bk[now])
now++;
if (now>=N) continue;
P[i]=pos_pre[now]; Q[i]=pos_bk[now];
swap(pre[pos_pre[now]],pre[pos_bk[now]]);
pos_pre[pre[pos_pre[now]]]=pos_pre[now];
pos_pre[pre[pos_bk[now]]]=pos_bk[now];
}
bool flag=1;
for (int i=0;i<N;i++){
if (pre[i]!=i) flag=0;
}
if (flag) return n;
else return 1e9;
}
int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
/*
int l=0,r=M;
while (l<r){
int mid=(l+r)>>1;
if (solve(N,mid,S,P,Q,X,Y)<1e8) r=mid;
else l=mid+1;
}
return solve(N,l,S,P,Q,X,Y);
*/
int mn=1e9,pos;
for (int i=0;i<M;i++){
int need=solve1(N,i,S,P,Q,X,Y);
if (need<1e8)
return solve1(N,pos,S,P,Q,X,Y);
}
}
Compilation message
sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:103:9: warning: unused variable 'mn' [-Wunused-variable]
103 | int mn=1e9,pos;
| ^~
sorting.cpp:109:1: warning: control reaches end of non-void function [-Wreturn-type]
109 | }
| ^
sorting.cpp:107:26: warning: 'pos' is used uninitialized in this function [-Wuninitialized]
107 | return solve1(N,pos,S,P,Q,X,Y);
| ~~~~~~^~~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Runtime error |
3 ms |
544 KB |
Execution killed with signal 11 |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Runtime error |
3 ms |
544 KB |
Execution killed with signal 11 |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Runtime error |
3 ms |
468 KB |
Execution killed with signal 11 |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Runtime error |
3 ms |
544 KB |
Execution killed with signal 11 |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
121 ms |
784 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
121 ms |
784 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |