Submission #955603

#	Time	Username	Problem	Language	Result	Execution time	Memory
955603		horiseun	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	189 ms	157144 KiB

shoes

#include <iostream>
#include <vector>
#include <queue>
#include <cstdlib>
#include <algorithm>
#include "shoes.h"
using namespace std;

#define ll long long

struct Node {
	int l, r, offset;
	Node *lft, *rht;
	Node (int tl, int tr): l(tl), r(tr), offset(0) {
		if (l + 1 != r) {
			lft = new Node(l, (l + r) / 2);
			rht = new Node((l + r) / 2, r);
		} else {
			lft = rht = NULL;
		}
	}
};

void update(Node *x, int l, int r, int v) {
	if (r <= x->l || x->r <= l) {
		return;
	}
	if (l <= x->l && x->r <= r) {
		x->offset += v;
		return;
	}
	update(x->lft, l, r, v);
	update(x->rht, l, r, v);
}

int query(Node *x, int pos) {
	if (pos < x->l || x->r <= pos) {
		return 0;
	}
	if (x->l + 1 == x->r) {
		return x->offset;
	}
	return query(x->lft, pos) + query(x->rht, pos) + x->offset;
}

Node *root;
queue<int> unpaired[100005][2];

ll count_swaps(vector<int> s) {
	root = new Node(0, s.size() + 5);
	ll ans = 0;
	for (int i = 0; i < s.size(); i++) {
		if (s[i] < 0) {
			if (unpaired[-s[i]][1].size()) {
				ans += i - (unpaired[-s[i]][1].front() + query(root, unpaired[-s[i]][1].front()));
				update(root, unpaired[-s[i]][1].front(), i + 1, 1);
				unpaired[-s[i]][1].pop();
			} else {
				unpaired[-s[i]][0].push(i);
			}
		} else {
			if (unpaired[s[i]][0].size()) {
				ans += i - (unpaired[s[i]][0].front() + query(root, unpaired[s[i]][0].front())) - 1;
				update(root, unpaired[s[i]][0].front(), i + 1, 1);
				unpaired[s[i]][0].pop();
			} else {
				unpaired[s[i]][1].push(i);
			}
		}	
	}
	return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:52:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   52 |  for (int i = 0; i < s.size(); i++) {
      |                  ~~^~~~~~~~~~

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