Submission #775553

#	Time	Username	Problem	Language	Result	Execution time	Memory
775553		1bin	Arranging Shoes (IOI19_shoes)	C++14	50 / 100	283 ms	364660 KiB

shoes

#include <bits/stdc++.h>
#include "shoes.h"

using namespace std;

#define all(v) v.begin(), v.end()
typedef long long ll;
const int b = 1 << 17;
int n, seg[b * 2], li, ri, l, r, n2;
queue<int> q[b * 2];

int find(){
    int ix = 1;
    while(ix < b){
        ix <<= 1;
        if(!seg[ix]) ix++;
    }
    return ix - b;
}

void upd(int ix){
    ix += b;
    while(ix) {
        seg[ix]--;
        ix /= 2;
    }
}

int sum(int l, int r){
    l += b; r += b;
    int ret = 0;
    while(l <= r){
        if(l & 1) ret += seg[l++];
        if(!(r & 1)) ret += seg[r--];
        l /= 2; r /= 2;
    }
    return ret;
}

ll count_swaps(vector<int> v){
    ll ans = 0; n = v.size(); n2 = n / 2;
    for(int i = 0; i < n; i++) {
        if(v[i] < 0) v[i] = -v[i];
        else v[i] = v[i] + n2;
        q[v[i]].emplace(i);
        seg[b + i] = 1;
    }
    
    for(int i = b - 1; i; i--) seg[i] = seg[i * 2] + seg[i * 2 + 1];
    for(int i = 0; i < n2; i++){
        li = find(); upd(li);
        l = v[li];
        q[l].pop();
        
        r = l > n2 ? l - n2 : l + n2;
        ri = q[r].front(); upd(ri);
        q[r].pop();
        ans += sum(0, ri) + (l > n2);
    }
    return ans;
}

/*
int main(void){
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    
    int n;
    cin >> n;
    vector<int> v(n);
    for(int& x : v) cin >> x;
    cout << count_swaps(v);
    
    return 0;
}
*/

/*
test1
4
2 1 -1 -2

test2
6
-2 2 -2 2 -2 2
*/

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