Submission #932948

#	Time	Username	Problem	Language	Result	Execution time	Memory
932948		velislavgarkov	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	46 ms	20824 KiB

shoes

#include "shoes.h"
#include <iostream>
#include <vector>
using namespace std;
const int MAXN=2e5+10;
vector <int> idx[MAXN][2];
int lef[MAXN], fen[MAXN];
bool sw[MAXN];
int n;
void update(int ind, int ch) {
	if (ind==0) return;
	while (ind<n) {
		fen[ind]+=ch;
		ind+=(ind & (-ind));
	}
}
int query(int ind) {
	if (ind==0) return 0;
	int res=0;
	while (ind>0) {
		res+=fen[ind];
		ind-=(ind & (-ind));
	}
	return res;
}
long long count_swaps(vector<int> s) {
	n=s.size();
	for (int i=0;i<n;i++) {
		if (s[i]<0) idx[-s[i]][0].push_back(i);
		else idx[s[i]][1].push_back(i);
		lef[i]=-1;
		sw[i]=false;
	}
	for (int i=0;i<n;i++) {
		if (idx[i][0].empty()) continue;
		for (int j=0;j<idx[i][0].size();j++) {
			if (idx[i][0][j]<idx[i][1][j]) lef[idx[i][1][j]]=idx[i][0][j];
			else {
				lef[idx[i][0][j]]=idx[i][1][j];
				sw[idx[i][0][j]]=true;
			}
		}
	}
	long long ans=0;
	for (int i=1;i<n;i++) {
		if (lef[i]==-1) update(i,1);
		else {
			long long s=query(i-1)-query(lef[i]);
			s+=sw[i];
			ans+=s;
			update(lef[i],1);
		}
	}
	return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:36:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |   for (int j=0;j<idx[i][0].size();j++) {
      |                ~^~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 15 / 15
• Subtask 5: 20 / 20
• Subtask 6: 15 / 15