Create Find Minimum Time to Reach Last Room I.java

Author: varunu28

Medium/Find Minimum Time to Reach Last Room I.java

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+class Solution {
+
+    private static final int[][] DIRS = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
+
+    public int minTimeToReach(int[][] moveTime) {
+        int n = moveTime.length;
+        int m = moveTime[0].length;
+        boolean[][] visited = new boolean[n][m];
+        Integer[][] minTime = new Integer[n][m];
+        minTime[0][0] = 0;
+        PriorityQueue<int[]> pq = new PriorityQueue<>((a, b) -> a[2] - b[2]);
+        pq.add(new int[]{0, 0, 0});
+        while (!pq.isEmpty()) {
+            int[] removed = pq.remove();
+            int x = removed[0];
+            int y = removed[1];
+            if (visited[x][y]) {
+                continue;
+            }
+            visited[x][y] = true;
+            for (int[] dir : DIRS) {
+                int newX = x + dir[0];
+                int newY = y + dir[1];
+                if (newX >= 0 && newY >= 0 && newX < n && newY < m) {
+                    int distance = Math.max(minTime[x][y], moveTime[newX][newY]) + 1;
+                    int currMinTime = minTime[newX][newY] == null ? Integer.MAX_VALUE : minTime[newX][newY];
+                    if (currMinTime > distance) {
+                        minTime[newX][newY] = distance;
+                        pq.add(new int[]{newX, newY, distance});
+                    }
+                }
+            }
+        }
+        return minTime[n - 1][m - 1];
+    }
+}