Create 2258-escape-the-spreading-fire.js

Author: everthis

2258-escape-the-spreading-fire.js

@@ -0,0 +1,103 @@
+/**
+ * @param {number[][]} grid
+ * @return {number}
+ */
+const maximumMinutes = function (grid) {
+  const [m, n] = [grid.length, grid[0].length]
+  const dir = [
+    [-1, 0],
+    [1, 0],
+    [0, -1],
+    [0, 1],
+  ]
+
+  function isValidCell(x, y) {
+    return x >= 0 && x < m && y >= 0 && y < n
+  }
+
+  const fireDist = new Array(m)
+  for (let i = 0; i < m; i++) {
+    fireDist[i] = new Array(n).fill(Infinity)
+  }
+
+  const firePoints = []
+  for (let i = 0; i < m; i++) {
+    for (let j = 0; j < n; j++) {
+      if (grid[i][j] === 1) {
+        firePoints.push([i, j])
+        fireDist[i][j] = 0
+      }
+    }
+  }
+
+  while (firePoints.length) {
+    const [x0, y0] = firePoints.shift()
+
+    for (const [dx, dy] of dir) {
+      const [x1, y1] = [x0 + dx, y0 + dy]
+
+      if (
+        isValidCell(x1, y1) &&
+        grid[x1][y1] === 0 &&
+        fireDist[x0][y0] + 1 < fireDist[x1][y1]
+      ) {
+        fireDist[x1][y1] = fireDist[x0][y0] + 1
+        firePoints.push([x1, y1])
+      }
+    }
+  }
+
+  function canEscape(delay) {
+    const visited = new Array(m)
+    for (let i = 0; i < m; i++) {
+      visited[i] = new Array(n).fill(false)
+    }
+
+    const queue = [[0, 0]]
+    let currMinutes = delay
+
+    while (queue.length) {
+      currMinutes++
+
+      for (let i = queue.length; i > 0; i--) {
+        const [i0, j0] = queue.shift()
+        visited[i0][j0] = true
+
+        for (const [di, dj] of dir) {
+          const [i1, j1] = [i0 + di, j0 + dj]
+
+          if (
+            isValidCell(i1, j1) &&
+            grid[i1][j1] === 0 &&
+            !visited[i1][j1] &&
+            (currMinutes < fireDist[i1][j1] ||
+              (currMinutes === fireDist[i1][j1] &&
+                i1 === m - 1 &&
+                j1 === n - 1))
+          ) {
+            if (i1 === m - 1 && j1 === n - 1) {
+              return true
+            }
+            queue.push([i1, j1])
+          }
+        }
+      }
+    }
+
+    return false
+  }
+
+  let [left, right] = [-1, 1_000_000_000]
+
+  while (left < right) {
+    const middle = Math.floor((left + right + 1) / 2)
+
+    if (canEscape(middle)) {
+      left = middle
+    } else {
+      right = middle - 1
+    }
+  }
+
+  return left
+}