Submission #200092

#	Time	Username	Problem	Language	Result	Execution time	Memory
200092		anonymous	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	140 ms	17528 KiB

shoes

#include "shoes.h"
#include<queue>
#define LL long long
#define MAXN 200005
using namespace std;
LL N, BIT[MAXN], ans;
priority_queue<int> PQ[MAXN>>1][2]; //only BIT is 1 indexed
bool del[MAXN];
int abs(int i) {return(i > 0 ? i : -i);}

void upd(int p, int v) {
    for (; p<=N+5; p+=p&(-p)) {BIT[p]+=v;}
}

LL ask(int p) {
    LL res=0;
    for (; p>0; p-=p&(-p)) {res+=BIT[p];}
    return(res);
}

long long count_swaps(std::vector<int> s) {
	N=s.size();
	for (int i=1; i<=N; i++) {
        upd(i,1);
        PQ[abs(s[i-1])][s[i-1]<0].push(1-i);
	}
	for (int i=0; i<N; i++) {
        if (del[i]) {continue;}
        LL v;
        while (true) {
            v=-PQ[abs(s[i])][s[i]>0].top();
            PQ[abs(s[i])][s[i]>0].pop();
            if (del[v]) {continue;}
            else {break;}
        }
        ans+=ask(v)-ask(i+1);
        if (s[i] > 0) {ans++;}
        del[i]=del[v]=true;
        upd(v+1, -1);
        upd(i+1, -1);
	}
	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