[최은서] Day20

leetcode2/1easy/최은서/Q2768.js

@@ -0,0 +1,40 @@
+/**
+ * @param {number} m
+ * @param {number} n
+ * @param {number[][]} coordinates
+ * @return {number[]}
+ */
+var countBlackBlocks = function (m, n, coordinates) {
+  //const dr = [0, -1, 1, 0, 0, -1]
+  //const dc = [0, 0, 0, -1, 1, -1];
+  const dr = [0, 0, -1, -1]; //검은 블록이 왼쪽 위, 오른쪽 위, 왼쪽 아래, 오른쪽 아래
+  const dc = [0, -1, 0, -1];
+  const arr = Array(5).fill(0);
+  arr[0] = (m - 1) * (n - 1);
+  const visited = new Set();
+  const black = new Set();
+  const key = (r, c) => `${r},${c}`;
+  for (const [r, c] of coordinates) {
+    black.add(key(r, c));
+  }
+  for (const [r, c] of coordinates) {
+    for (let i = 0; i < 4; i++) {
+      const nr = r + dr[i];
+      const nc = c + dc[i];
+      let total = 0;
+      if (nr < 0 || nr >= m - 1 || nc < 0 || nc >= n - 1) continue;
+      const k = key(nr, nc);
+      if (!visited.has(k)) {
+        total =
+          (black.has(key(nr, nc)) ? 1 : 0) +
+          (black.has(key(nr, nc + 1)) ? 1 : 0) +
+          (black.has(key(nr + 1, nc)) ? 1 : 0) +
+          (black.has(key(nr + 1, nc + 1)) ? 1 : 0);
+        arr[total] += 1;
+        arr[0] -= 1;
+        visited.add(k);
+      }
+    }
+  }
+  return arr;
+};