Submission #440291

#	Time	Username	Problem	Language	Result	Execution time	Memory
440291		adamjinwei	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	125 ms	73420 KiB

shoes

#include <bits/stdc++.h>
#include "shoes.h"
#define inf 1000000007
#define mod 1000000007
#define lowbit(x) (x&(-x))
#define rnd() rand_num()
#define bigrnd() dis(rand_num)
//#pragma GCC optimize("Ofast","inline","-ffast-math")
//#pragma GCC target("avx,sse2,sse3,sse4,mmx")
//#define int long long
using namespace std;
unsigned sed=std::chrono::system_clock::now().time_since_epoch().count();
mt19937 rand_num(sed);
uniform_int_distribution<long long> dis(0,inf);
template <typename T> void read(T &x){
	x=0;char ch=getchar();int fh=1;
	while (ch<'0'||ch>'9'){if (ch=='-')fh=-1;ch=getchar();}
	while (ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();
	x*=fh;
}
template <typename T> void write(T x) {
	if (x<0) x=-x,putchar('-');
	if (x>9) write(x/10);
	putchar(x%10+'0');
}
template <typename T> void writeln(T x) {
	write(x);
	puts("");
}
int n;
int s[200005];
int b[200005];
bool vis[200005];
queue<int> q[100005];
int bit[200005];
void modify(int x,int y)
{
	while(x<=2*n)
	{
		bit[x]+=y;
		x+=lowbit(x);
	}
}
int query(int x)
{
	int res=0;
	while(x)
	{
		res+=bit[x];
		x-=lowbit(x);
	}
	return res;
}
long long count_swaps(vector<int> S)
{
	n=S.size()/2;
	for(int i=1;i<=2*n;++i)
	{
		s[i]=S[i-1];
		if(s[i]<0)
			q[-s[i]].push(i);
	}
	long long ans=0;
	for(int i=1;i<=2*n;++i)
		if(s[i]>0)
		{
			b[i]=q[s[i]].front();
			b[q[s[i]].front()]=i;
			if(i<q[s[i]].front()) ans++;
			q[s[i]].pop();
		}
	for(int i=1;i<=2*n;++i)
		modify(i,1);
	for(int i=1;i<=2*n;++i)
	{
		if(vis[i]) continue;
		ans+=query(b[i]-1)-query(i);
		modify(b[i],-1);
		modify(i,-1);
		vis[b[i]]=vis[i]=1;
	}
	return ans;
}

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