Submission #164558

#	Time	Username	Problem	Language	Result	Execution time	Memory
164558		cfalas	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	594 ms	150028 KiB

shoes

#include<bits/stdc++.h>
using namespace std;
#include "shoes.h"
#define F first
#define S second
#define MID ((l+r)/2)
long long seg[700000];
long long n;

void build(long long l=0, long long r=n, long long ind=1){
	if(l==r) seg[ind] = 1;
	else{
		build(l, MID, ind*2);
		build(MID+1, r, ind*2+1);
		seg[ind] = seg[ind*2] + seg[ind*2+1];
	}
}

void update(long long p, long long l=0, long long r=n, long long ind=1){
	if(l==r && l==p) seg[ind] = 0;
	else if(r<p || l>p || l==r) return;
	else{
		update(p, l, MID, ind*2);
		update(p, MID+1, r, ind*2+1);
		seg[ind] = seg[ind*2] + seg[ind*2+1];
	}
}

long long query(long long rl, long long rr, long long l=0, long long r=n, long long ind=1){
	if(rl<=l && r<=rr) return seg[ind];
	else if(r<rl || l>rr) return 0;
	else return query(rl, rr, l, MID, ind*2) + query(rl, rr, MID+1, r, ind*2+1);
}
 
long long count_swaps(std::vector<int> s) {
	n = s.size();
	build();
	long long swaps=0;
	long long ind = 0;
	unordered_map<long long, queue<long long> > m;
	for(long long i=0;i<s.size();i++){
		m[s[i]].push(i);
	}
	while(ind<s.size()){
		if(m[s[ind]].size()==0 || m[s[ind]].front() !=ind){
			ind++;
			continue;
		}
		if(s[ind]>0) swaps++;

		long long i = m[-s[ind]].front();
		swaps += query(ind+1, i-1);
		//swaps += (i-ind-1);
		update(m[s[i]].front());
		//cout<<query(ind, i)<<endl;
		m[-s[ind]].pop();
		m[s[ind]].pop();
		ind++;
		//cout<<endl<<endl<<endl;
	}
	return swaps;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:41:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(long long i=0;i<s.size();i++){
                    ~^~~~~~~~~
shoes.cpp:44:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while(ind<s.size()){
        ~~~^~~~~~~~~

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