Submission #466408

#	Time	Username	Problem	Language	Result	Execution time	Memory
466408		NintsiChkhaidze	Arranging Shoes (IOI19_shoes)	C++14	50 / 100	148 ms	51620 KiB

shoes

#include "shoes.h"
#include <vector>
#include <algorithm>
#include <set>
#define pb push_back
#define ll long long
#define left (h<<1),l,((l+r)>>1)
#define right ((h<<1)|1),((l+r)>>1) + 1,r
using namespace std;

const int N = 100010;
set <int> neg[N],post[N];
ll t[4*N],add[4*N];
pair<int,pair<int,int> > d[N/2];

void push(int h,int l,int r){
    if (!add[h]) return;

    t[h*2] += add[h]*((l+r)/2 - l + 1);
    t[h*2 + 1] += add[h]*(r - (l+r)/2);

    add[h*2] += add[h];
    add[h*2 + 1] += add[h];

    add[h] = 0;
}
void upd(int h,int l,int r,int L,int R,int val){
    if (r < L || R < l) return ;
    if (L <= l && r <= R){
        t[h] += val*(r-l+1);
        add[h] += val;
        return;
    }
    push(h,l,r);
    upd(left,L,R,val),upd(right,L,R,val);
    t[h] = t[h*2] + t[h*2 + 1];
}

ll get(int h,int l,int r,int idx){
    if (l == r) return t[h];
    push(h,l,r);
    if (idx > (l+r)/2) return get(right,idx);
    return get(left,idx);
}
ll count_swaps(vector <int> a) {
    int n = a.size();
    for (int i = 0; i < a.size(); i++){
        if (a[i] < 0) neg[-a[i]].insert(i);
        else post[a[i]].insert(i);
    }

    ll cnt = 0;
    for (int i = 0; i < a.size(); i++){

        if (a[i] < 0){
            if (*neg[-a[i]].begin() != i) continue;
            neg[-a[i]].erase(neg[-a[i]].begin());
            int ind = *post[-a[i]].begin();

            post[-a[i]].erase(post[-a[i]].begin());
            d[++cnt] = {abs(ind - i),{i,ind}};
        }
        else{
            if (*post[a[i]].begin() != i) continue;
            post[a[i]].erase(post[a[i]].begin());

            int ind = *neg[a[i]].begin();

            neg[a[i]].erase(neg[a[i]].begin());
            d[++cnt] = {abs(ind - i),{ind,i}};
        }
    }
    sort(d + 1,d + cnt + 1);

    ll ans=0;
    for (int i = 1; i <= cnt; i++){
        int l = d[i].second.first,r = d[i].second.second;
        if (l > r) swap(l,r);
        ans += r - l - 1 - get(1,1,n, l + 1) - get(1,1,n,r + 1);
        if (a[l] > 0 && a[r] < 0) ans++;

        upd(1,1,n,l + 2, r,1);
    }

    return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:47:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   47 |     for (int i = 0; i < a.size(); i++){
      |                     ~~^~~~~~~~~~
shoes.cpp:53:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |     for (int i = 0; i < a.size(); i++){
      |                     ~~^~~~~~~~~~

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