Submission #722849

#	Time	Username	Problem	Language	Result	Execution time	Memory
722849		Darren0724	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	91 ms	19084 KiB

shoes

#include "shoes.h"
#include<bits/stdc++.h>
//#include "grader.cpp"
using namespace std;

int n;
vector<int> v;
void add(int p,int x){
    for(int i=p;i<=n;i+=i&(-i)){
        v[i]+=x;
    }
}
int ask(int p){
    int ans=0;
    for(int i=p;i>0;i-=i&(-i)){
        ans+=v[i];
    }
    return ans;
}
int ask(int a,int b){
    return ask(b+1)-ask(a);
}
long long count_swaps(std::vector<int> s) {
    n=s.size();
    v.resize(n+1);
    vector<int> a[n+1],b[n+1];
    for(int i=0;i<n;i++){
        if(s[i]>0){
            b[s[i]].push_back(i);
        }
        else{
            a[-s[i]].push_back(i);
        }
    }
    vector<int> match(n);
    for(int i=0;i<=n;i++){
        int tmp=a[i].size();
        for(int j=0;j<tmp;j++){
            match[a[i][j]]=b[i][j];
            match[b[i][j]]=a[i][j];
        }
    }
    for(int i=0;i<n;i++){
        add(i+1,1);
    }
    long long ans=0;
    for(int i=0;i<n;i++){
        if(match[i]<i){
            continue;
        }
        if(s[i]<0){
            int p=match[i];
            ans+=ask(i+1,p-1);
            add(i+1,-1);
            add(p+1,-1);
        }
        else{
            int p=match[i];
            ans+=ask(i+1,p-1)+1;
            add(i+1,-1);
            add(p+1,-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