Create 803-bricks-falling-when-hit.js

Author: everthis

803-bricks-falling-when-hit.js

@@ -0,0 +1,68 @@
+/**
+ * @param {number[][]} grid
+ * @param {number[][]} hits
+ * @return {number[]}
+ */
+const hitBricks = function (grid, hits) {
+  const n = grid[0].length
+  const m = hits.length
+  const res = new Array(m).fill(0)
+  for (const [r, c] of hits) {
+    if (grid[r][c] == 1) grid[r][c] = 0
+    else grid[r][c] = -1
+  }
+  for (let j = 0; j < n; j++) {
+    getConnectedCount(grid, 0, j)
+  }
+  for (let i = m - 1; i >= 0; i--) {
+    const [r, c] = hits[i]
+    if (grid[r][c] == -1) continue
+    grid[r][c] = 1
+    if (isConnectedToTop(grid, r, c)) {
+      res[i] = getConnectedCount(grid, r, c) - 1
+    }
+  }
+  return res
+}
+const isConnectedToTop = (grid, i, j) => {
+  if (i == 0) return true
+  const dircs = [
+    [-1, 0],
+    [1, 0],
+    [0, -1],
+    [0, 1],
+  ]
+  for (const [dx, dy] of dircs) {
+    const nx = i + dx
+    const ny = j + dy
+    if (
+      0 <= nx &&
+      nx < grid.length &&
+      0 <= ny &&
+      ny < grid[0].length &&
+      grid[nx][ny] == 2
+    ) {
+      return true
+    }
+  }
+  return false
+}
+
+const getConnectedCount = (grid, i, j) => {
+  if (
+    i < 0 ||
+    i >= grid.length ||
+    j < 0 ||
+    j >= grid[0].length ||
+    grid[i][j] != 1
+  )
+    return 0
+  let count = 1
+  grid[i][j] = 2
+  count +=
+    getConnectedCount(grid, i + 1, j) +
+    getConnectedCount(grid, i - 1, j) +
+    getConnectedCount(grid, i, j + 1) +
+    getConnectedCount(grid, i, j - 1)
+  return count
+}