Submission #114939

#	Time	Username	Problem	Language	Result	Execution time	Memory
114939		jwvg0425	산악 구조대 (JOI13_mountain)	C++17	0 / 100	12 ms	896 KiB

mountain

#include <algorithm>
#include "grader.h"
#define xx first
#define yy second

using namespace std;
using ii = pair<int, int>;

int GetH(int R, int C, int RS, int CS, int D)
{
	int ans = 1000000001;

	if (D < 0)
		return ans;

	ii pos[] = {
		{RS - D, CS },
		{RS + D, CS },
		{RS, CS - D },
		{RS, CS + D }
	};

	for (int i = 0; i < 4; i++)
	{
		if (pos[i].xx >= 1 && pos[i].xx <= R && pos[i].yy >= 1 && pos[i].yy <= C)
		{
			ans = min(ans, Measure(pos[i].xx, pos[i].yy));
			continue;
		}

		//젤 먼 두 개로 분할
		int x1 = pos[i].xx, y1 = pos[i].yy;
		int x2 = x1, y2 = y1;

		if (x1 < 1)
		{
			int g = 1 - x1;
			x1 = x2 = 1;
			y1 -= g;
			y2 += g;
		}
		else if (x1 > R)
		{
			int g = x1 - R;
			x1 = x2 = R;
			y1 -= g;
			y2 += g;
		}
		else if (y1 < 1)
		{
			int g = 1 - y1;
			y1 = y2 = 1;
			x1 -= g;
			x2 += g;
		}
		else if (y1 > C)
		{
			int g = y1 - C;
			y1 = y2 = C;
			x1 -= g;
			x2 += g;
		}

		if (x1 >= 1 && x1 <= R && y1 >= 1 && y1 <= C)
			ans = min(ans, Measure(x1, y1));

		if (x2 >= 1 && x2 <= R && y2 >= 1 && y2 <= C)
			ans = min(ans, Measure(x2, y2));
	}

	return ans;
}

bool Find(int R, int C, int RS, int CS, int D, int X)
{
	if (D == 0)
	{
		int h = Measure(RS, CS);

		if (h == X)
		{
			Pinpoint(RS, CS);
			return true;
		}

		return false;
	}

	int sx = RS - D, sy = CS;
	int dx[] = { 0, 1, 1, -1, -1 };
	int dy[] = { 0, 1, -1, -1, 1 };
	int di = 0;

	for(int i = 0; i < 4 * D; i++, sx += dx[di], sy += dy[di])
	{
		if (i % D == 0)
			di++;

		if (sx < 1 || sx > R || sy < 1 || sy > C)
			continue;

		int h = Measure(sx, sy);

		if (h == X)
		{
			Pinpoint(sx, sy);
			return true;
		}
	}

	return false;
}

void Rescue(int R, int C, int RS, int CS, int X) {
	// 모서리 4개, 가운데 4개로 max, min을 특정할 수 있다.
	// 속하는 영역을 이분 탐색으로 찾은 후 거기 밀기

	int l = 0, r = max(R - RS, RS - 1) + max(C - CS, CS - 1);
	int ans = r;

	while (l <= r)
	{
		int mid = (l + r) / 2;

		int nowMin = GetH(R, C, RS, CS, mid);
		int upMin = GetH(R, C, RS, CS, mid - 1);

		if (nowMin <= X && X <= upMin)
		{
			ans = mid;
			break;
		}

		if (nowMin < X)
			r = mid;
		else
			l = mid;
	}

	// ans거리에서 탐색
	if (!Find(R, C, RS, CS, ans, X))
		Find(R, C, RS, CS, ans - 1, X);
}

• Subtask 1: 0 / 20
• Subtask 2: 0 / 80