Week 51

지은/boj/2573.cpp

@@ -0,0 +1,104 @@
+#include <iostream>
+#include <cstring>
+#include <queue>
+using namespace std;
+
+int n, m, year, cnt;
+int snow[301][301];
+int melt[301][301];
+bool visited[301][301];
+queue<pair<int, int>> q;
+
+int dy[] = { 1,0,-1,0 };
+int dx[] = { 0,1,0,-1 };
+
+void addYear() {
+	while (!q.empty()) {
+		int cur_y = q.front().first;
+		int cur_x = q.front().second;
+		q.pop();
+
+		for (int i = 0; i < 4; i++) {
+			int next_y = cur_y + dy[i];
+			int next_x = cur_x + dx[i];
+
+			if (snow[next_y][next_x] != 0)
+				continue;
+
+			melt[cur_y][cur_x]++;
+		}
+	}
+	for (int i = 0; i < n; i++) {
+		for (int j = 0; j < m; j++) {
+			snow[i][j] = (snow[i][j] - melt[i][j] > 0) ? snow[i][j] - melt[i][j] : 0;
+		}
+	}
+	year++;
+}
+
+void getCnt(int y, int x) {
+	q.push({ y, x });
+	visited[y][x] = true;
+
+	while (!q.empty()) {
+		int cur_y = q.front().first;
+		int cur_x = q.front().second;
+		q.pop();
+
+		for (int i = 0; i < 4; i++) {
+			int next_y = cur_y + dy[i];
+			int next_x = cur_x + dx[i];
+
+			if (visited[next_y][next_x] || snow[next_y][next_x] == 0)
+				continue;
+
+			q.push({ next_y, next_x });
+			visited[next_y][next_x] = true;
+		}
+	}
+}
+
+int main() {
+	cin >> n >> m;
+
+	for (int i = 0; i < n; i++) {
+		for (int j = 0; j < m; j++) {
+			cin >> snow[i][j];
+		}
+	}
+
+	while (true) {
+		memset(melt, 0, sizeof(melt));
+		for (int i = 0; i < n; i++) {
+			for (int j = 0; j < m; j++) {
+				if (snow[i][j] > 0) {
+					q.push({ i,j });
+				}
+			}
+		}
+
+		addYear();
+
+		cnt = 0;
+		memset(visited, false, sizeof(visited));
+		for (int i = 0; i < n; i++) {
+			for (int j = 0; j < m; j++) {
+				if (!visited[i][j] && snow[i][j] > 0) {
+					getCnt(i, j);
+					cnt++;
+				}
+			}
+		}
+
+		if (cnt >= 2) {
+			cout << year;
+			break;
+		}
+		else if (cnt == 0) {
+			cout << 0;
+			break;
+		}
+	}
+
+	return 0;
+}