Submission #1098446

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
1098446	2024-10-09T11:49:12 Z	alexander707070	Sorting (IOI15_sorting)	C++14	Compilation error	0 ms	0 KB

sorting

#include<bits/stdc++.h>
#include "sorting.h"

#define MAXN 200007
using namespace std;

int n,m,q,br;
int pos[MAXN],s[MAXN],post[MAXN];

int to[MAXN];

int check(int stop, int S[], int X[], int Y[], int P[], int Q[]){
	for(int i=0;i<n;i++)s[i]=i;
	for(int i=0;i<stop;i++)swap(s[X[i]],s[Y[i]]);

	for(int i=0;i<n;i++)to[s[i]]=i;
	for(int i=0;i<n;i++){
		s[i]=S[i]; pos[s[i]]=i;
		post[to[i]]=i;
	}

	int pt=0;
	for(int i=0;i<stop;i++){
		P[i]=Q[i]=0;

		swap(s[X[i]],s[Y[i]]);
		swap(to[X[i]],to[Y[i]]);

		swap(pos[s[X[i]]],pos[s[Y[i]]]);
		swap(post[to[X[i]]],post[to[Y[i]]]);

		while(pt<n and to[pos[pt]]==pt)pt++;
		if(pt==n)continue;

		P[i]=pos[pt]; Q[i]=post[pt];

		swap(s[P[i]],s[Q[i]]);
		swap(pos[s[P[i]]],pos[s[Q[i]]]);
	}

	q=stop; br=0;
	for(int i=0;i<n;i++){
		s[i]=S[i];
		if(s[i]==i)br++;
	}

	for(int i=0;i<stop;i++){
		if(br==n)return i;

		if(s[X[i]]==X[i])br--;
		if(s[Y[i]]==Y[i])br--;

		swap(s[X[i]],s[Y[i]]);

		if(s[X[i]]==X[i])br++;
		if(s[Y[i]]==Y[i])br++;

		if(s[P[i]]==P[i])br--;
		if(s[Q[i]]==Q[i])br--;
		
		swap(s[P[i]],s[Q[i]]);

		if(s[P[i]]==P[i])br++;
		if(s[Q[i]]==Q[i])br++;
	}

	if(br==n)return q;

	return -1;
}


int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
    n=N; m=M;

	int l=-1,r=n,tt;
	while(l+1<r){
		int tt=(l+r)/2;
		if(check(tt,S,X,Y,P,Q)!=-1){
			r=tt;
		}else{
			l=tt;
		}
	}

	return check(r);
}

Compilation message

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:78:7: warning: declaration of 'tt' shadows a previous local [-Wshadow]
   78 |   int tt=(l+r)/2;
      |       ^~
sorting.cpp:76:15: note: shadowed declaration is here
   76 |  int l=-1,r=n,tt;
      |               ^~
sorting.cpp:86:16: error: too few arguments to function 'int check(int, int*, int*, int*, int*, int*)'
   86 |  return check(r);
      |                ^
sorting.cpp:12:5: note: declared here
   12 | int check(int stop, int S[], int X[], int Y[], int P[], int Q[]){
      |     ^~~~~
sorting.cpp:76:15: warning: unused variable 'tt' [-Wunused-variable]
   76 |  int l=-1,r=n,tt;
      |               ^~