graph - bfs iter O(rc) O(1)

Author: lukeist

_leetcode_from-blind75-26w40h/w1-44-!!!-01Matrix.js renamed to _leetcode_from-blind75-26w40h/w1-44-!!2-01Matrix.js

@@ -0,0 +1,49 @@
+/**
+ * @param {number[][]} mat
+ * @return {number[][]}
+ */
+
+// p: grid m x n;
+// r: grid m x n;
+// e:
+//
+//
+// [[0,0,0],
+//  [0,1,0],
+//  [1,1,1]]
+//
+//
+
+var updateMatrix = function (mat) {
+  const queue = [];
+  for (let i = 0; i < mat.length; i++) {
+    for (let j = 0; j < mat[0].length; j++) {
+      if (mat[i][j] === 0) {
+        queue.push([i, j, 0]);
+      } else {
+        mat[i][j] = -1;
+      }
+    }
+  }
+
+  while (queue.length > 0) {
+    const [y, x, d] = queue.shift();
+    const deltas = [
+      [y + 1, x],
+      [y - 1, x],
+      [y, x + 1],
+      [y, x - 1],
+    ];
+    for (let [neiY, neiX] of deltas) {
+      const boundY = 0 <= neiY && neiY < mat.length;
+      const boundX = 0 <= neiX && neiX < mat[0].length;
+
+      if (boundY && boundX && mat[neiY][neiX] === -1) {
+        mat[neiY][neiX] = d + 1;
+        queue.push([neiY, neiX, d + 1]);
+      }
+    }
+  }
+
+  return mat;
+};