Submission #679373

#	Time	Username	Problem	Language	Result	Execution time	Memory
679373		Nahian9696	Arranging Shoes (IOI19_shoes)	C++17	50 / 100	102 ms	20872 KiB

shoes

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

using namespace std;

#define f0(i, n) for(int i = 0; i < n; i++)
#define f1(i, n) for(int i = 1; i <= n; i++)

bool compare(pair<int, int> p1, pair<int, int> p2) {
	int ind1 = p1.first + p1.second;
	int ind2 = p2.first + p2.second;
	if(p1.first > p1.second) ind1++;
	if(p2.first > p2.second) ind2++;
	return ind1 < ind2;
}

class segment_tree {
	private:
	int size, size_n;
	vector<int> tree;

	public:
	segment_tree(int n, vector<int> arr) {
		int base = 1;
		while(base < 2*n) base *= 2;
		size = base;
		tree.resize(size, 0);
		base /= 2;
		size_n = base;
		f0(i, n) tree[i + base] = arr[i];
		for(int i = base - 1; i >= 0; i--) {
			tree[i] = tree[2*i] + tree[2*i + 1];
		}
	}
	void update(int ind, int val) {
		ind += size_n;
		int delta = val - tree[ind];
		while(ind > 0) {
			tree[ind] += delta;
			ind /= 2;
		}
	}
	int query(int l, int r) {
		l += size_n;
		r += size_n;
		int res = 0;
		while( l <= r) {
			if(l % 2 == 1) {
				res += tree[l];
				l++;
			}
			if(r % 2 == 0) {
				res += tree[r];
				r--;
			}
			l /= 2;
			r /= 2;
		}
		return res;
	}
};

long long count_swaps(std::vector<int> s) {
	int n = s.size()/2;
	vector<pair<int, int>> pp;

	vector<int> v[n+1][2];

	f0(i, 2*n) {
		if(s[i] < 0) {
			v[-s[i]][0].push_back(i);
		} else {
			v[s[i]][1].push_back(i);
		}
	}

	f1(i, n) {
		f0(j, v[i][0].size()) {
			pp.push_back({v[i][0][j], v[i][1][j]});
		}
	}

	sort(pp.begin(), pp.end(), compare);

	long long ans[2*n];
	long long ans2[2*n];


	f0(i, n) {
		ans[2*i] = pp[i].first;
		ans[2*i + 1] = pp[i].second;
		ans2[pp[i].first] = 2*i;
		ans2[pp[i].second] = 2*i + 1;
		// ans += abs(pp[i].first - 2*i);
		// ans += abs(pp[i].second - 2*i - 1);
		// cout << pp[i].first << " " << 2*i << " " << pp[i].second << " " << 2*i + 1 << endl;
	}

	segment_tree st(2*n, vector<int>(2*n, 0));

	int ret = 0;

	f0(i, 2*n) {
		ret += ans2[i];
		ret -= st.query(0, ans2[i]);
		st.update(ans2[i], 1);
	}

	return ret;
	// return ans;


	return 1;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:6:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    6 | #define f0(i, n) for(int i = 0; i < n; i++)
......
   78 |   f0(j, v[i][0].size()) {
      |      ~~~~~~~~~~~~~~~~~             
shoes.cpp:78:3: note: in expansion of macro 'f0'
   78 |   f0(j, v[i][0].size()) {
      |   ^~
shoes.cpp:85:12: warning: variable 'ans' set but not used [-Wunused-but-set-variable]
   85 |  long long ans[2*n];
      |            ^~~

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