Submission #204122

#	Time	Username	Problem	Language	Result	Execution time	Memory
204122		medk	Arranging Shoes (IOI19_shoes)	C++14	0 / 100	1080 ms	256 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>> pos;

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);
    pos.resize(n/2+1);
    for(int i=0;i<n;i++) pos[S[i]].pb(i+1);
    vector<int> pt(n/2+1,0);
    for(int i=1;i<=n;i++)
    {
        if(a[i]==0) continue;
        ans+=sm(i+1,pos[S[i-1]][pt[S[i-1]]+1]-1);
        a[i]=0, a[pos[S[i-1]][pt[S[i-1]]+1]]=0;
        update(i,-1), update(pos[S[i-1]][pt[S[i-1]]+1],-1);
        pt[S[i-1]]+=2;
    }
    return ans;
}

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