Submission #1263876

#	Time	Username	Problem	Language	Result	Execution time	Memory
1263876		piolk	Arranging Shoes (IOI19_shoes)	C++20	100 / 100	223 ms	274164 KiB

shoes

#include <bits/stdc++.h>
using namespace std;

vector<int> tree;
int len=0;

void update(int v,int currStart,int currEnd,int lookStart,int lookEnd){
    if (currStart>=lookStart && currEnd<=lookEnd){
        tree[v]++;
        return;
    }

    if (currStart>lookEnd || currEnd<lookStart) return;

    int mid=(currStart+currEnd)/2;
    update(2*v,currStart,mid,lookStart,lookEnd);
    update(2*v+1,mid+1,currEnd,lookStart,lookEnd);
}

int get(int pos){
    pos+=len;
    int ans=tree[pos];

    while (pos>1){
        pos/=2;
        ans+=tree[pos];
    }
    return ans;
}

int64_t count_swaps(vector<int> S){
    tree.clear();
    int n=S.size();

    for (int i=1;i<=21;i++){
        int p=(1<<i);
        if (p>=n){
            len=p;
            break;
        }
    }

    tree.resize(2*len);

    vector<bool> skip(n);
    iota(tree.begin()+len+1,tree.end(),1);
    vector<pair<queue<int>,queue<int>>> pqs(n+1);

    for (int i=0;i<n;i++){
        if (S[i]>0){
            pqs[S[i]].first.push(i);
        } else {
            pqs[S[i]*-1].second.push(i);
        }
    }

    int64_t swaps=0;

    for (int i=0;i<n;i++){
        if (skip[i]) continue;

        int now=get(i);
        int next;

        if (S[i]>0){
            //szukam w ujemnych na .second
            next=pqs[S[i]].second.front();
            pqs[S[i]].second.pop();

            pqs[S[i]].first.pop(); //usuwamy now
        } else {
            //szukam w dodatnich na .first
            next=pqs[S[i]*-1].first.front();
            pqs[S[i]*-1].first.pop();

            pqs[S[i]*-1].second.pop();//usuwamy now
        }

        update(1,0,len-1,0,next-1);

        skip[i]=true;
        skip[next]=true;

        next=get(next);

        swaps+=next-now-1;

        if (S[i]>0) swaps++;
    }
    return swaps;
}

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