Create Solution.java

Jerring · web-flow · commit 6368ca663f4e · 2019-06-18T21:16:24.000+08:00
diff --git a/solution/0542.01 Matrix/Solution.java b/solution/0542.01 Matrix/Solution.java
@@ -0,0 +1,38 @@
+class Solution {
+    public int[][] updateMatrix(int[][] matrix) {
+        int m = matrix.length, n = matrix[0].length;
+        int[][] res = new int[m][n];
+        for (int[] arr : res) {
+            Arrays.fill(arr, -1);
+        }
+        class Position {
+            int x, y;
+
+            public Position(int x, int y) {
+                this.x = x;
+                this.y = y;
+            }
+        }
+        Queue<Position> queue = new ArrayDeque<>();
+        for (int i = 0; i < m; ++i) {
+            for (int j = 0; j < n; ++j) {
+                if (matrix[i][j] == 0) {
+                    res[i][j] = 0;
+                    queue.offer(new Position(i, j));
+                }
+            }
+        }
+        int[] dirs = new int[]{-1, 0, 1, 0, -1};
+        while (!queue.isEmpty()) {
+            Position pos = queue.poll();
+            for (int i = 0; i < 4; ++i) {
+                int x = pos.x + dirs[i], y = pos.y + dirs[i + 1];
+                if (x >= 0 && x < m && y >= 0 && y < n && res[x][y] == -1) {
+                    res[x][y] = res[pos.x][pos.y] + 1;
+                    queue.offer(new Position(x, y));
+                }
+            }
+        }
+        return res;
+    }
+}
