Submission #1203261

#	Time	Username	Problem	Language	Result	Execution time	Memory
1203261		SpyrosAliv	Arranging Shoes (IOI19_shoes)	C++20	100 / 100	117 ms	15560 KiB

shoes

#include <bits/stdc++.h>
using namespace std;
#define ll long long

int n;
vector<int> a;

class Segtree {
    private:
    int n;
    vector<int> seg;
    void update(int node, int l, int r, int idx) {
        if (l == r) seg[node] = 1;
        else {
            int mid = (l + r) / 2;
            if (idx <= mid) update(node*2+1, l, mid, idx);
            else update(node*2+2, mid+1, r, idx);
            seg[node] = seg[node*2 + 1] + seg[node*2 + 2]; 
        }
    }
    int query(int node, int start, int end, int l, int r) {
        if (start > r || end < l) return 0;
        else if (start >= l && end <= r) return seg[node];
        else {
            int mid = (start + end) / 2;
            return query(node*2+1, start, mid, l, r) + query(node*2+2, mid+1, end, l, r);
        }
    }
    public:
    void init(int nn) {
        n = nn;
        seg.assign(n*4, 0);
    }
    void update(int idx) {
        update(0, 0, n-1, idx);
    }
    int query(int l, int r) {
        if (l > r) return 0;
        return query(0, 0, n-1, l, r);
    }
} seg;

int get_dis(int pos, int a, int b) {
    a += seg.query(a+1, (2*n)-1);
    b += seg.query(b+1, (2*n)-1);
    int bon = a > b;
    return abs(a - pos) + abs((b + bon) - (pos + 1));
}

ll count_swaps(vector<int> s) {
    n = s.size();
    seg.init(n);
    a = s;
    int c = 0;
    vector<int> r(n/2, 0), l(n/2, 0);
    vector<vector<int>> poss(n+1);
    for (int i = 0; i < n; i++) {
        poss[abs(s[i])].push_back(i);
    }
    for (int i = 1; i <= n; i++) {
        vector<int> L, R;
        for (auto j: poss[i]) {
            if (abs(s[j]) != i) continue;
            if (s[j] < 0) L.push_back(j);
            else R.push_back(j);
        }
        int sz = L.size();
        for (int j = 0; j < sz; j++) {
            l[c] = L[j];
            r[c] = R[j];
            c++;
        }
    }
    n /= 2;
    vector<pair<int, int>> ord;
    for (int i = 0; i < n; i++) {
        ord.push_back({get_dis(0, l[i], r[i]), i});
    }
    ll ans = 0;
    sort(ord.begin(), ord.end());
    int pos = 0;
    for (auto [u, v]: ord) {
        ans += get_dis(pos, l[v], r[v]);
        seg.update(l[v]);
        seg.update(r[v]);
        pos += 2;
    }   
    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