Submission #790169

#	Time	Username	Problem	Language	Result	Execution time	Memory
790169		PoonYaPat	Sorting (IOI15_sorting)	C++14	54 / 100	7 ms	10332 KiB

sorting

#include "sorting.h"
#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;

int n,m,b[200005],x[200005],y[200005],p[200005],cnt;
vector<pii> ans,v;
vector<int> adj[200005],group[200005],temp;
int a[200005],pos[200005],val[200005],c[200005];
bool vis[200005];

void dfs(int x, int st) {
	temp.push_back(x);
	vis[x]=true;
	for (auto s : adj[x]) {
		if (s==st) for (auto s : temp) group[cnt].push_back(s);
		else dfs(s,st);
	}
	temp.pop_back();
}


bool check(int h, bool mode) {
	v.clear();
	cnt=0;
	memset(vis,0,sizeof(vis));
	for (int i=0; i<n; ++i) a[i]=i, val[i]=i, c[i]=b[i], p[i]=i, adj[i].clear(), group[i].clear();
	for (int i=h; i>=0; --i) swap(a[x[i]],a[y[i]]);

	for (int i=0; i<n; ++i) pos[a[i]]=i;
	for (int i=0; i<n; ++i) adj[i].push_back(pos[c[i]]);

	for (int i=0; i<n; ++i) {
		if (!vis[i]) {
			if (adj[i][0]==i) continue;
			dfs(i,i);
			for (int j=0; j<group[cnt].size()-1; ++j) v.push_back(pii(group[cnt][j],group[cnt][j+1]));
			++cnt;
		}
	}

	if (mode) {
		int cnt=0;
		for (int i=0; i<=h; ++i) {
			swap(val[p[x[i]]],val[p[y[i]]]);
			swap(p[x[i]],p[y[i]]);

			if (v.size()) {
				ans.push_back(pii(val[v.back().first],val[v.back().second]));
				v.pop_back();
			} else ans.push_back(pii(0,0));
		}
	}

	if (v.size()<=h+1) return true;
	else return false;
}

int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
	n=N; m=M;
	for (int i=0; i<n; ++i) b[i]=S[i], x[i]=X[i], y[i]=Y[i];

	int l=0, r=m-1;
	while (l<r) {
		int mid=(l+r)/2;
		if (check(mid,0)) r=mid;
		else l=mid+1;
	}
	check(l,1);

	for (int i=0; i<ans.size(); ++i) P[i]=ans[i].first, Q[i]=ans[i].second;
	return ans.size();
}

Compilation message (stderr)

sorting.cpp: In function 'void dfs(int, int)':
sorting.cpp:12:14: warning: declaration of 'x' shadows a global declaration [-Wshadow]
   12 | void dfs(int x, int st) {
      |          ~~~~^
sorting.cpp:6:19: note: shadowed declaration is here
    6 | int n,m,b[200005],x[200005],y[200005],p[200005],cnt;
      |                   ^
sorting.cpp:16:24: warning: declaration of 's' shadows a previous local [-Wshadow]
   16 |   if (s==st) for (auto s : temp) group[cnt].push_back(s);
      |                        ^
sorting.cpp:15:12: note: shadowed declaration is here
   15 |  for (auto s : adj[x]) {
      |            ^
sorting.cpp: In function 'bool check(int, bool)':
sorting.cpp:37:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   37 |    for (int j=0; j<group[cnt].size()-1; ++j) v.push_back(pii(group[cnt][j],group[cnt][j+1]));
      |                  ~^~~~~~~~~~~~~~~~~~~~
sorting.cpp:43:7: warning: declaration of 'cnt' shadows a global declaration [-Wshadow]
   43 |   int cnt=0;
      |       ^~~
sorting.cpp:6:49: note: shadowed declaration is here
    6 | int n,m,b[200005],x[200005],y[200005],p[200005],cnt;
      |                                                 ^~~
sorting.cpp:43:7: warning: unused variable 'cnt' [-Wunused-variable]
   43 |   int cnt=0;
      |       ^~~
sorting.cpp:55:14: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   55 |  if (v.size()<=h+1) return true;
      |      ~~~~~~~~^~~~~
sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:71:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   71 |  for (int i=0; i<ans.size(); ++i) P[i]=ans[i].first, Q[i]=ans[i].second;
      |                ~^~~~~~~~~~~
sorting.cpp:72:17: warning: conversion from 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   72 |  return ans.size();
      |         ~~~~~~~~^~

• Subtask 1: 8 / 8
• Subtask 2: 12 / 12
• Subtask 3: 16 / 16
• Subtask 4: 18 / 18
• Subtask 5: 0 / 20
• Subtask 6: 0 / 26