Language: C++

#include <iostream>
#include <array>
#include <algorithm>
#include <map>
#include <vector>
#include <list>
#include <cmath>
#include <stack>
#include <queue>
#include <climits>
#include <string.h>
#include <cctype>
#include <set>

#define rep(i,n) for (int i = 0; i < (n); ++i)
using namespace std;
using ll = long long;
using P = pair<int, int>;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }

// a と b の最大公約数を返す関数
long long GCD(long long a, long long b) {
	if (b == 0) return a;
	else return GCD(b, a % b);
}

long long gcd(long long a, long long b)
{
	if (a % b == 0)
	{
		return(b);
	}
	else
	{
		return(gcd(b, a % b));
	}
}

long long lcm(long long a, long long b)
{
	return a * b / gcd(a, b);
}

// auto mod int
// https://youtu.be/L8grWxBlIZ4?t=9858
// https://youtu.be/ERZuLAxZffQ?t=4807 : optimize
// https://youtu.be/8uowVvQ_-Mo?t=1329 : division
const int mod = 1000000007;
struct mint {
	ll x; // typedef long long ll;
	mint(ll x = 0) :x((x% mod + mod) % mod) {}
	mint operator-() const { return mint(-x); }
	mint& operator+=(const mint a) {
		if ((x += a.x) >= mod) x -= mod;
		return *this;
	}
	mint& operator-=(const mint a) {
		if ((x += mod - a.x) >= mod) x -= mod;
		return *this;
	}
	mint& operator*=(const mint a) { (x *= a.x) %= mod; return *this; }
	mint operator+(const mint a) const { return mint(*this) += a; }
	mint operator-(const mint a) const { return mint(*this) -= a; }
	mint operator*(const mint a) const { return mint(*this) *= a; }
	mint pow(ll t) const {
		if (!t) return 1;
		mint a = pow(t >> 1);
		a *= a;
		if (t & 1) a *= *this;
		return a;
	}

	// for prime mod
	mint inv() const { return pow(mod - 2); }
	mint& operator/=(const mint a) { return *this *= a.inv(); }
	mint operator/(const mint a) const { return mint(*this) /= a; }
};
istream& operator>>(istream& is, const mint& a) { return is >> a.x; }
ostream& operator<<(ostream& os, const mint& a) { return os << a.x; }

struct combination {
	vector<mint> fact, ifact;
	combination(int n) :fact(n + 1), ifact(n + 1) {
		fact[0] = 1;
		for (int i = 1; i <= n; ++i) fact[i] = fact[i - 1] * i;
		ifact[n] = fact[n].inv();
		for (int i = n; i >= 1; --i) ifact[i - 1] = ifact[i] * i;
	}
	mint operator()(int n, int k) {
		if (k < 0 || k > n) return 0;
		return fact[n] * ifact[k] * ifact[n - k];
	}
} comb(2000005);

mint g(int r, int c) {
	return comb(r + c + 2, r + 1) - 1;
}

bool comp(int i, int j) {
	return i > j;
}

bool compare_by_b(pair<int, int> a, pair<int, int> b) {
	return a.second < b.second;
}

long tall[200000];
long long diff[200000];
vector<int> que;

// index が条件を満たすかどうか
bool isOK(int index, int key) {
	if (que[index] >= key) return true;
	else return false;
}

// 汎用的な二分探索のテンプレ
int binary_search(int key) {
	int left = -1; //「index = 0」が条件を満たすこともあるので、初期値は -1
	int right = (int)que.size(); // 「index = a.size()-1」が条件を満たさないこともあるので、初期値は a.size()

	/* どんな二分探索でもここの書き方を変えずにできる！ */
	while (right - left > 1) {
		int mid = left + (right - left) / 2;

		if (isOK(mid, key)) right = mid;
		else left = mid;
	}

	/* left は条件を満たさない最大の値、right は条件を満たす最小の値になっている */
	return right;
}

long long modpow(long long a, long long n, long long mod) {
	long long res = 1;
	while (n > 0) {
		if (n & 1) res = res * a % mod;
		a = a * a % mod;
	}
	return res;
}

int hasu[1000000];
int h, w, k;
int xx1, yy1, xx2, yy2;

//0から
void hasuin(int x, int y, int val)
{
	hasu[x * w + y] = val;
}

int basyo(int x, int y)
{
	return x * w + y;
}

int baX(int val)
{
	return val / w;
}

int baY(int val)
{
	return val % w;
}

bool isIn(int x, int y)
{
	return x >= 0 && x < h && y >= 0 && y < w;
}

int main()
{
	cin >> h >> w >> k;
	cin >> xx1 >> yy1 >> xx2 >> yy2;

	for (int i = 0; i < h; i++)
	{
		for (int j = 0; j < w; j++)
		{
			hasuin(i, j, -1);

			char ch;
			cin >> ch;

			if (ch == '@')
			{
				hasuin(i, j, -10);
			}
		}
	}

	queue<pair<int, int>> q;
	q.push(make_pair(basyo(xx2 - 1, yy2 - 1), 0));

	while (q.size() > 0)
	{
		pair<int, int> ne = q.front();
		q.pop();
		int pos = ne.first;
		int x = baX(pos);
		int y = baY(pos);

		if (hasu[basyo(x, y)] != -1)
		{
			continue;
		}
		if (x == xx1 - 1 && y == yy1 - 1)
		{
			cout << ne.second;
			return 0;
		}

		hasuin(x, y, ne.second);

		if (x == xx1 - 1)
		{
			if (yy1 - y > 0)
			{
				for (int i = 1; i <= yy1 - y; i++)
				{
					if (!hasu[basyo(x, y + i)])
					{
						break;
					}
				}
				cout << (ne.second + (yy1 - y) / k);
			}
			else
			{
				for (int i = 1; i <= y - yy1; i++)
				{
					if (!hasu[basyo(x, y - i)])
					{
						break;
					}
				}
				cout << (ne.second + (yy1 - y) / k);
			}
		}
		if (y == yy1 - 1)
		{
			if (xx1 - x > 0)
			{
				for (int i = 1; i <= xx1 - x; i++)
				{
					if (!hasu[basyo(x + i, y)])
					{
						break;
					}
				}
				cout << (ne.second + (xx1 - x) / k);
			}
			else
			{
				for (int i = 1; i <= x - xx1; i++)
				{
					if (!hasu[basyo(x - i)])
					{
						break;
					}
				}
				cout << (ne.second + (x - xx1) / k);
			}
		}
		for (int i = 1; i <= k; i++)
		{
			if (!isIn(x + i, y))
			{
				break;
			}
			if (hasu[basyo(x + i, y)] != -1)
			{
				break;
			}

			q.push(make_pair(basyo(x + i, y), ne.second + 1));
		}
		for (int i = 1; i <= k; i++)
		{
			if (!isIn(x - i, y))
			{
				break;
			}
			if (hasu[basyo(x - i, y)] != -1)
			{
				break;
			}

			q.push(make_pair(basyo(x - i, y), ne.second + 1));
		}
		for (int i = 1; i <= k; i++)
		{
			if (!isIn(x, y + i))
			{
				break;
			}
			if (hasu[basyo(x, y + i)] != -1)
			{
				break;
			}

			q.push(make_pair(basyo(x, y + i), ne.second + 1));
		}
		for (int i = 1; i <= k; i++)
		{
			if (!isIn(x, y - i))
			{
				break;
			}
			if (hasu[basyo(x, y - i)] != -1)
			{
				break;
			}

			q.push(make_pair(basyo(x, y - i), ne.second + 1));
		}
	}

	cout << "-1";
}


Compiler output:
a.cc: In function 'int main()':
a.cc:260:56: error: too few arguments to function 'int basyo(int, int)'
  260 |                                         if (!hasu[basyo(x - i)])
      |                                                   ~~~~~^~~~~~~
a.cc:154:5: note: declared here
  154 | int basyo(int x, int y)
      |     ^~~~~