Submission #722845

#	Time	Username	Problem	Language	Result	Execution time	Memory
722845		Darren0724	Arranging Shoes (IOI19_shoes)	C++17	15 / 100	63 ms	11700 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)-ask(a-1);
}
long long count_swaps(std::vector<int> s) {
    n=s.size();
    int m=n/2;
    v.resize(n+1);
    vector<int> a[n+1];
    for(int i=m*2-1;i>=m;i--){
        a[s[i]].push_back(i);
    }
    for(int i=0;i<n;i++){
        add(i+1,1);
    }
    long long ans=0;
    for(int i=0;i<m;i++){
        s[i]=-s[i];
        int p=a[s[i]].back();
        a[s[i]].pop_back();
        ans+=ask(i+1,p-1);
        add(p,-1);
    }
    return ans;
}

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