Submission #16564

#	Time	Username	Problem	Language	Result	Execution time	Memory
16564		gs14004	Sorting (IOI15_sorting)	C++14	100 / 100	784 ms	13816 KiB

sorting

#include "sorting.h"
#include <algorithm>
using namespace std;

int *s, *x, *y, *p, *q, n;
int obj[200005], cur[200005];
int orev[200005], crev[200005];

bool trial(int t){
	for(int i=0; i<n; i++){
		obj[i] = i;
	}
	for(int i=t-1; i>=0; i--){
		swap(obj[x[i]], obj[y[i]]);
	}
	for(int i=0; i<n; i++){
		orev[obj[i]] = i;
		cur[i] = s[i];
		crev[cur[i]] = i;
	}
	int pt = 0;
	for(int i=0; i<t; i++){
		swap(obj[x[i]], obj[y[i]]);
		swap(cur[x[i]], cur[y[i]]);
		crev[cur[x[i]]] = x[i];
		orev[obj[x[i]]] = x[i];
		crev[cur[y[i]]] = y[i];
		orev[obj[y[i]]] = y[i];
		while(pt < n && crev[pt] == orev[pt]) pt++;
		if(pt == n){
			p[i] = q[i] = 0;
			continue;
		}
		int p1 = crev[pt];
		int p2 = orev[pt];
		p[i] = p1;
		q[i] = p2;
		swap(cur[p1], cur[p2]);
		crev[cur[p1]] = p1;
		crev[cur[p2]] = p2;
	}
	while(pt < n && crev[pt] == orev[pt]) pt++;
	return (pt == n);
}

int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
	n = N, s = S, x = X, y = Y, p = P, q = Q;
	int s = 0, e = M;
	while(s != e){
		int m = (s+e)/2;
		if(trial(m)) e = m;
		else s = m+1;
	}
	trial(s);
	return s;
}

Compilation message (stderr)

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:48:6: warning: declaration of 's' shadows a global declaration [-Wshadow]
  int s = 0, e = M;
      ^
sorting.cpp:5:6: note: shadowed declaration is here
 int *s, *x, *y, *p, *q, n;
      ^

• Subtask 1: 8 / 8
• Subtask 2: 12 / 12
• Subtask 3: 16 / 16
• Subtask 4: 18 / 18
• Subtask 5: 20 / 20
• Subtask 6: 26 / 26