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LeetCode solutions

3627. Find Minimum Time to Reach Last Room I

My accepted Python solution to LeetCode problem 3627, Find Minimum Time to Reach Last Room I, running in 135ms.

  • Difficulty: Medium
  • Python
  • Runtime 135ms
  • Memory 17.9MB

Read the problem on LeetCode View on GitHub

The problem statement is LeetCode’s and stays on their site. What follows is my accepted solution.

Python

Accepted on LeetCode — runtime 135ms, memory 17.9MB, accepted 2025-12-31.

python
class Solution:
    def minTimeToReach(self, moveTime: List[List[int]]) -> int:
        import heapq
        n, m = len(moveTime), len(moveTime[0])
        dist = [[float('inf')] * m for _ in range(n)]
        dist[0][0] = 0
        pq = [(0, 0, 0)]  # (time, row, col)
        
        while pq:
            t, r, c = heapq.heappop(pq)
            if r == n - 1 and c == m - 1:
                return t
            if t > dist[r][c]:
                continue
            for dr, dc in [(0, 1), (0, -1), (1, 0), (-1, 0)]:
                nr, nc = r + dr, c + dc
                if 0 <= nr < n and 0 <= nc < m:
                    # Wait until moveTime[nr][nc] if necessary, then move (1 sec)
                    new_time = max(t, moveTime[nr][nc]) + 1
                    if new_time < dist[nr][nc]:
                        dist[nr][nc] = new_time
                        heapq.heappush(pq, (new_time, nr, nc))
        
        return dist[n-1][m-1]

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