Submission #114941

#	Time	Username	Problem	Language	Result	Execution time	Memory
114941		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;

	int ds[] = {
		RS + CS - 2,
		R - RS + CS - 1,
		R + C - RS - CS,
		RS - 1 + C - CS
	};

	int md = *max_element(ds, ds + 4);

	if (md == ds[0])
		if (RS > CS)
			return Measure(RS - (D + 1) / 2, CS - D / 2);
		else
			return Measure(RS - D / 2, CS - (D + 1) / 2);

	if (md == ds[1])
		if (R - RS > CS - 1)
			return Measure(RS + (D + 1) / 2, CS - D / 2);
		else
			return  Measure(RS + D / 2, CS - (D + 1)  / 2);

	if (md == ds[2])
		if (R - RS > C - CS)
			return Measure(RS + (D + 1) / 2, CS + D / 2);
		else
			return Measure(RS + D / 2, CS + (D + 1) / 2);

	if (RS - 1 > C - CS)
		return Measure(RS - (D + 1) / 2, CS + D / 2);
	else
		return Measure(RS - D / 2, CS + (D + 1) / 2);
}

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 = 1, 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 - 1;
		else
			l = mid + 1;
	}

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

Compilation message (stderr)

mountain.cpp: In function 'int GetH(int, int, int, int, int)':
mountain.cpp:25:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
  if (md == ds[0])
     ^
mountain.cpp:31:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
  if (md == ds[1])
     ^
mountain.cpp:37:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
  if (md == ds[2])
     ^

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