Spiraali

#include <math.h>
#include <iostream>
#include <string>
#include <vector>
using namespace std;

long long l(int x, int y, int n);
long long k(int k, int n);

int main()
{
	int n, t, x, y, i;
	vector<long long> v;
	cin >> n >> t;

	for (i = 0; i < t; i++) {
		cin >> x >> y;
		v.push_back(l(x, y, n));
	}

	for (auto i : v)
	{
		cout << i << "\n";
	}
}

long long k(int k, int n) { 
	long long l = (k*(4 * n - 4 + (4 * (n - 2 * (k - 1) - 4)))) / 2;
	return l;
}

long long l(int x, int y, int n) {
	if (x == n / 2 && y == n / 2 + 1) return n*n;
	if (x < y) {
		int r = n - x + 1;
		if (y <= r) {
			int k = x - 1;
			long long l = (k*(4 * n - 4 + (4 * (n - 2 * (k - 1)) - 4))) / 2;
			l += n - (2 * k);
			l += 2 * (n - 2 * k - 1);

			l += (n - 2 * k) - (y - k);
			return l;
		}
		else
		{
			int k = n - y;
			long long l = (k*(4 * n - 4 + (4 * (n - 2 * (k - 1)) - 4))) / 2;
			l += n - (2 * k);
			l += n - 2 * k - 1;
			
			l += y - x;
			return l;
		}
	}
	else if (x == y) {
		if (x <= n / 2)
		{
			int k = x - 1;
			long long l = (k*(4 * n - 4 + (4 * (n - 2 * (k - 1)) - 4))) / 2;
			return l + 1;
		}
		else
		{
			int k = n - x;
			long long l = (k*(4 * n - 4 + (4 * (n - 2 * (k - 1)) - 4))) / 2;
			l += n - 2 * k;
			l += n - 2 * k - 1;
			return l;
		}
	}
	else
	{
		int r = n - y + 1;
		if (x <= r)
		{
			int k = y - 1;
			long long l = (k*(4 * n - 4 + (4 * (n - 2 * (k - 1)) - 4))) / 2;

			l += x - k;
			return l;
		}
		else
		{
			int k = n - x;
			long long l = (k*(4 * n - 4 + (4 * (n - 2 * (k - 1)) - 4))) / 2;
			l += n - 2 * k;

			l += y - 1 - k;
			return l;
		}
	}
	/*
	if (x < y) {
		int k = n - x + 1;
		if (y <= k) {
			long long l = 0;
			if (x > 1) l += ((x-1)*((4 * n - 4 + (4 * (n - 2 * (x - 2)) - 4))))/2;
			l += n - 2 * (x - 1);
			l += 2 * (n - 2 * (x - 1) - 1);
			l += n - y - (x - 1);
			return l;
		}
		else
		{
			k = n - y;
			long long l = 0;
			l += ((k)*(4 * n - 4 + (4 * (n - 2 * (k - 1)) - 4))) / 2;
			l += n - 2 * k;
			l += n - 2 * k - 1;
			l += (n - 2 * k) - (x - k);
			return l;
		}
	}
	else if (x == y) {
		if (x <= n / 2)
		{
			long long l = 1;
			l += ((x - 1) * ((4 * n - 4 + (4 * (n - 2 * (x - 2)) - 4)))) / 2;
			return l;
		}
		else
		{
			int k = n - x;
			long long l = 0;
			l += ((k) * ((4 * n - 4 + (4 * (n - 2 * (k - 1)) - 4)))) / 2;
			l += 2 * (n - 2 * k);
			return l - 1;
		}
	}
	else 
	{
		int k = n - y + 1;
		if (x <= k) {
			long long l = 0;
			if (x > 1) l += ((y - 1)*((4 * n - 4 + (4 * (n - 2 * (y - 2)) - 4)))) / 2;
			l += x - (y - 1);
			return l;
		}
		else
		{
			k = n - x;
			long long l = 0;
			l += (k*((4 * n - 4 + (4 * (n - 2 * (k - 1)) - 4)))) / 2;
			l += n - 2 * k - 1;
			l += y - k;
			return l;
		}
	}
	*/
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: ACCEPTED

Test 3

Group: 3

Verdict: WRONG ANSWER