[20250220] BOJ / G4 / 거울 / 권혁준

khj20006/202502/20 BOJ G4 거울.md

@@ -0,0 +1,40 @@
+```cpp
+
+#include <iostream>
+#include <algorithm>
+using namespace std;
+
+int A[1002][1002]{}, N, M, ans[4001]{};
+int dx[2] = { -1,0 };
+int dy[2] = { 0,1 };
+
+int main()
+{
+	cin.tie(0)->sync_with_stdio(0);
+
+	cin >> N >> M;
+	for (int i = 1; i <= N; i++) for (int j = 1; j <= M; j++) cin >> A[i][j];
+
+	int cnt = 0;
+	for (int i = 1; i <= N; i++) A[i][0] = ++cnt;
+	for (int j = 1; j <= M; j++) A[N + 1][j] = ++cnt;
+	for (int i = N; i >= 1; i--) A[i][M + 1] = ++cnt;
+	for (int j = M; j >= 1; j--) A[0][j] = ++cnt;
+
+	for (int cur = 1; cur <= N + M; cur++) {
+		int x = min(N, cur), y = max(1, cur - N), dir = cur <= N;
+		while (1 <= x && x <= N && 1 <= y && y <= M) {
+			if (A[x][y]) dir ^= 1;
+			x += dx[dir], y += dy[dir];
+		}
+
+		int from = cur, to = A[x][y];
+		ans[from] = to;
+		ans[to] = from;
+	}
+
+	for (int i = 1; i <= cnt; i++) cout << ans[i] << ' ';
+
+}
+
+```