Submission #428256

#	Time	Username	Problem	Language	Result	Execution time	Memory
428256		Hazem	Arranging Shoes (IOI19_shoes)	C++14	50 / 100	1098 ms	2412 KiB

shoes

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

#define LL long long
#define F first
#define S second

using namespace std;

const int N = 1e6+10;

vector<pair<LL,LL>>vec;
bool matched[N];
LL tree[N][2];

void update(int v,int tl,int tr,int pos ,int val,int t){

	if(tl==tr){
		tree[v][t] += val;
		return ;
	}

	int mid = (tl+tr)/2;
	if(pos<=mid)
		update(v*2,tl,mid,pos,val,t);
	else 
		update(v*2+1,mid+1,tr,pos,val,t);

	tree[v][t] = tree[v*2][t]+tree[v*2+1][t];
}

LL get(int v,int tl,int tr,int l,int r,int t){

	if(tl>r||tr<l)
		return 0;
	
	if(tl>=l&&tr<=r)
		return tree[v][t];
	
	int mid = (tl+tr)/2;
	return get(v*2,tl,mid,l,r,t)+get(v*2+1,mid+1,tr,l,r,t);
}

long long count_swaps(std::vector<int> s) {
	
	LL n = s.size()/2,ans = 0;
	int cnt = 0;

	for(int i=0;i<n*2;i++){
		if(s[i]<0){
			bool q = 0;
			for(int j=0;j<i;j++)
				if(s[j]==abs(s[i])&&!matched[j]){
					vec.push_back({j,i});ans += abs(i-j);
					q = 1;
					matched[j] = 1;
					break;
				}
			if(q)continue;

			for(int j=i+1;j<n*2;j++)
				if(s[j]==abs(s[i])&&!matched[j]){
					vec.push_back({i,j});ans += abs(i-j)-1;
					matched[j] = 1;
					break;
				}
		}
	}

	for(auto x:vec){
		update(1,1,n*2,x.F,1,0);
		update(1,1,n*2,x.S,1,1);
	}
	
	sort(vec.begin(),vec.end());
	for(int i=0;i<vec.size();i++){
		update(1,1,n*2,vec[i].F,-1,0);
		update(1,1,n*2,vec[i].S,-1,1);
		ans -= get(1,1,n*2,vec[i].S,n*2,1);
		ans += get(1,1,n*2,vec[i].S,n*2,0);
	}
	return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:76:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |  for(int i=0;i<vec.size();i++){
      |              ~^~~~~~~~~~~
shoes.cpp:47:6: warning: unused variable 'cnt' [-Wunused-variable]
   47 |  int cnt = 0;
      |      ^~~

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 15
• Subtask 5: 20 / 20
• Subtask 6: 0 / 15