Submission #1021869

#	Time	Username	Problem	Language	Result	Execution time	Memory
1021869		KasymK	Arranging Shoes (IOI19_shoes)	C++17	0 / 100	18 ms	29020 KiB

shoes

#include "bits/stdc++.h"
using namespace std;
#define pb push_back
#define ll long long
#define ff first
#define ss second
#define all(v) v.begin(), v.end()

const int N = 3e5+5;
set<int> S[N];
int bel[N], en[N], st[N], cnt[N], vis[N];

ll count_swaps(vector<int> v){
    int n = (int)v.size(), ad = sqrt(n), _ = -1;
    for(int i = 0; i < n; ++i){
        int pk = i/ad;
        bel[i] = pk, en[pk] = i, cnt[pk]++;
        if(pk > _)
            st[pk] = i;
        pk = _;
    }
    for(int i = 0; i < n; ++i)
        S[v[i]+n].insert(i);
    ll ans = 0;
    for(int i = 0; i < n-1; ++i){
        if(vis[i])
            continue;
        ans += (v[i] > 0 ? 1 : 0);
        auto a = S[-v[i]+n].upper_bound(i);
        S[-v[i]+n].erase(a);
        int j = *a;
        vis[j] = 1, cnt[bel[j]]--;
        if(bel[i+1] == bel[j-1] or i+1 > j-1){
            for(int k = i+1; k < j; ++k)
                ans += (!vis[k]);
            continue;
        }
        for(int k = i+1; k <= en[bel[i+1]]; ++k)
            ans += (!vis[k]);
        for(int k = j-1; k <= st[bel[j-1]]; ++k)
            ans += (!vis[k]);
        for(int k = bel[i+1]+1; k < bel[j-1]; ++k)
            ans += cnt[k];
    }
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:45:1: warning: no return statement in function returning non-void [-Wreturn-type]
   45 | }
      | ^

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