Submission #204166

#	Time	Username	Problem	Language	Result	Execution time	Memory
204166		medk	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	115 ms	15980 KiB

shoes

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

#define ll long long
#define pb push_back
#define x first
#define y second

using namespace std;

int n;
vector<int> a,bit;
vector<vector<int>> p1,p2;

void update(int x, int val)
{
    for(;x<=n;x+=x&-x)
        bit[x]+=val;
}

ll pre(int x)
{
    ll ret=0;
    for(;x>0;x-=x&-x)
        ret+=bit[x];
    return ret;
}

ll sm(int l, int r)
{
    return pre(r)-pre(l-1);
}

ll count_swaps(vector<int> S)
{
    ll ans=0;
    n=S.size();
    bit.resize(n+1);
    a.pb(0);
    for(int i=1;i<=n;i++) a.pb(1), update(i,1);
    p1.resize(n/2+1), p2=p1;
    for(int i=0;i<n;i++)
    {
        if(S[i]>0) p1[S[i]].pb(i+1);
        else p2[-S[i]].pb(i+1);
    }
    vector<int> pt(n/2+1,0);
    for(int i=1;i<=n;i++)
    {
        if(a[i]==0) continue;
        if(S[i-1]>0)
        {
            ans+=sm(i+1,p2[S[i-1]][pt[S[i-1]]]-1)+1;
            a[p2[S[i-1]][pt[S[i-1]]]]=0;
            update(i,-1), update(p2[S[i-1]][pt[S[i-1]]],-1);
            pt[S[i-1]]++;
        }
        else
        {
            ans+=sm(i+1,p1[-S[i-1]][pt[-S[i-1]]]-1);
            a[p1[-S[i-1]][pt[-S[i-1]]]]=0;
            update(i,-1), update(p1[-S[i-1]][pt[-S[i-1]]],-1);
            pt[-S[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