Submission #544135

#	Time	Username	Problem	Language	Result	Execution time	Memory
544135		krit3379	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	71 ms	20336 KiB

shoes

#include<bits/stdc++.h>
using namespace std;
#define N 400005

int fen[N],cnt[N];
long long ans;
vector<int> v[N];
bitset<N> vis;

void update(int x,int k){
    while(x<N){
        fen[x]+=k;
        x+=x&-x;
    }
}

int sol(int x){
    int ans=0;
    while(x){
        ans+=fen[x];
        x-=x&-x;
    }
    return ans;
}

long long count_swaps(vector<int> s){
    int n,i,now,nxt,pos;
    n=s.size();
    s.insert(s.begin(),0);
    for(i=1;i<=n;i++)fen[i]=i&-i;
    for(i=1;i<=n;i++)v[(s[i]>0)?s[i]:-s[i]+n].push_back(i);
    for(i=1;i<=n;i++){
        if(vis[i])continue;
        if(s[i]>0)now=s[i],nxt=s[i]+n;
        else now=-s[i]+n,nxt=-s[i];
        cnt[now]++;
        pos=v[nxt][cnt[nxt]++];
        ans+=sol(pos)-sol(i);
        if(s[i]<0)ans--;
        update(i,1);
        update(pos,-1);
        vis[i]=vis[pos]=true;
    }
    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