Submission #395335

#	Time	Username	Problem	Language	Result	Execution time	Memory
395335		ja_kingy	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	99 ms	19528 KiB

shoes

#include "shoes.h"
using namespace std;

const int mxN = 2e5+10;
vector<int> of_type[2*mxN];
int bit[mxN];

void upd(int x) {for (x++; x<mxN; x+=x&-x) bit[x]++;}

int qry(int x) {
	int res = 0;
	for (x++; x; x-=x&-x) res += bit[x];
	return res;
}

long long count_swaps(std::vector<int> s) {
	long long ans = 0;
	for (int i = s.size(); i--;) {
		of_type[s[i]+mxN].push_back(i);
	}
	for (int i = 0; i < s.size(); ++i) {
		if (of_type[s[i]+mxN].size() && i == of_type[s[i]+mxN].back()) {
			int x = of_type[mxN-s[i]].back();
			ans += x - i + (s[i] > 0) - qry(x) + qry(i) - 1;
			upd(x);
			of_type[s[i]+mxN].pop_back();
			of_type[mxN-s[i]].pop_back();
		}
	}
	return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:21:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |  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