Submission #417201

#	Time	Username	Problem	Language	Result	Execution time	Memory
417201		snasibov05	Arranging Shoes (IOI19_shoes)	C++14	45 / 100	327 ms	28192 KiB

shoes

#include "shoes.h"
#include <map>

using namespace std;

struct SegmentTree{
    vector<int> t;
    SegmentTree(int n){
        t.resize(4*n+5);
    }

    void assign(int v, int tl, int tr, int idx, int val){
        if (tl == tr){
            t[v] = val;
            return;
        }

        int tm = (tl + tr) / 2;
        if (idx <= tm) assign(v*2, tl, tm, idx, val);
        else assign(v*2+1, tm+1, tr, idx, val);

        t[v] = t[v*2] + t[v*2+1];
    }

    int getkth(int v, int tl, int tr, int k){
        if (tl == tr) return tl;

        int tm = (tl + tr) / 2;
        if (t[v*2] >= k) return getkth(v*2, tl, tm, k);
        else return getkth(v*2+1, tm+1, tr, k - t[v*2]);
    }

    int sum(int v, int tl, int tr, int l, int r){
        if (tl == l && tr == r) return t[v];

        int tm = (tl + tr) / 2;
        int res = 0;
        if (l <= tm) res += sum(v*2, tl, tm, l, min(r, tm));
        if (r > tm) res += sum(v*2+1, tm+1, tr, max(l, tm+1), r);
        return res;
    }
};

long long count_swaps(vector<int> s) {
	map<int, vector<int>> mp;
    int n = s.size();
    SegmentTree tree(n);
    for (int i = n-1; i >= 0; --i) {
        tree.assign(1, 0, n-1, i, 1);
        mp[s[i]].push_back(i);
    }

    long long ans = 0;
    for (int i = 0; i < n / 2; ++i) {
        int x = tree.getkth(1, 0, n-1, 1);
        int y = tree.sum(1, 0, n-1, 0, mp[-s[x]].back()) - 1;
        ans += max(y - 1, 0) * 1ll;
        if (s[x] > 0) ans++;
        tree.assign(1, 0, n-1, x, 0);
        tree.assign(1, 0, n-1, mp[-s[x]].back(), 0);
        mp[-s[x]].pop_back();
    }

    return ans;

}

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