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2577: Minimum Time to Visit a Cell In a Grid
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‎README.md

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@@ -34,6 +34,7 @@ My solutions to LeetCode problems in Kotlin.
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| [2275](https://leetcode.com/problems/largest-combination-with-bitwise-and-greater-than-zero/) | [Largest Combination With Bitwise AND Greater Than Zero](src/main/kotlin/com/schmoczer/leetcode/_2275/LargestCombination.kt) | Medium |
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| [2490](https://leetcode.com/problems/circular-sentence/) | [Circular Sentence](src/main/kotlin/com/schmoczer/leetcode/_2490/CircularSentence.kt) | Easy |
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| [2516](https://leetcode.com/problems/take-k-of-each-character-from-left-and-right/) | [Take K of Each Character From Left and Right](src/main/kotlin/com/schmoczer/leetcode/_2516/TakeKOfEachCharacterFromLeftAndRight.kt) | Medium |
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| [2577](https://leetcode.com/problems/minimum-time-to-visit-a-cell-in-a-grid/) | [Minimum Time to Visit a Cell In a Grid](src/main/kotlin/com/schmoczer/leetcode/_2577/MinimumTimeToVisitCellInGrid.kt) | Hard |
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| [2914](https://leetcode.com/problems/minimum-number-of-changes-to-make-binary-string-beautiful/) | [Minimum Number of Changes to Make Binary String Beautiful](src/main/kotlin/com/schmoczer/leetcode/_2914/MinChanges.kt) | Medium |
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| [2924](https://leetcode.com/problems/find-champion-ii/) | [Find Champion II](src/main/kotlin/com/schmoczer/leetcode/_2924/FindChampionII.kt) | Medium |
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| [3011](https://leetcode.com/problems/find-if-array-can-be-sorted/) | [Find if Array Can Be Sorted](src/main/kotlin/com/schmoczer/leetcode/_3011/FindIfArrayCanBeSorted.kt) | Medium |
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package com.schmoczer.leetcode._2577
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import java.util.*
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class MinimumTimeToVisitCellInGrid {
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// Runtime 142ms Beats 100.00%
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fun minimumTime(grid: Array<IntArray>): Int {
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if (grid[0][1] > 1 && grid[1][0] > 1) {
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return -1
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}
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val lastRow = grid.size - 1
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val lastColumn = grid.first().size - 1
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val directions = arrayOf(intArrayOf(1, 0), intArrayOf(-1, 0), intArrayOf(0, 1), intArrayOf(0, -1))
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val queue = PriorityQueue<IntArray>(compareBy { it[2] })
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queue.offer(intArrayOf(0, 0, 0))
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while (queue.isNotEmpty()) {
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val (currentRow, currentColumn, currentTime) = queue.poll()
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if (currentRow == lastRow && currentColumn == lastColumn) {
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return currentTime
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}
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grid[currentRow][currentColumn] = -1
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for (i in 0 until 4) {
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val nextRow = currentRow + directions[i][0]
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val nextColumn = currentColumn + directions[i][1]
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if (nextRow in 0..lastRow && nextColumn in 0..lastColumn && grid[nextRow][nextColumn] > -1) {
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val difference = grid[nextRow][nextColumn] - currentTime
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val nextTime = currentTime + if (difference < 2) {
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1
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} else if (difference % 2 == 0) {
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difference + 1
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} else {
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difference
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}
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queue.offer(intArrayOf(nextRow, nextColumn, nextTime))
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grid[nextRow][nextColumn] = -1
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}
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}
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}
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return -1
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}
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}
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# Minimum Time to Visit a Cell In a Grid
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You are given a `m x n` matrix `grid` consisting of non-negative integers where `grid[row][col]` represents the minimum
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time required to be able to visit the cell `(row, col)`, which means you can visit the cell `(row, col)` only when the
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time you visit it is greater than or equal to `grid[row][col]`.
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You are standing in the top-left cell of the matrix in the `0`'th second, and you must move to any adjacent cell in the
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four directions: up, down, left, and right. Each move you make takes 1 second.
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Return the minimum time required in which you can visit the bottom-right cell of the matrix. If you cannot visit the
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bottom-right cell, then return `-1`.
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Example 1:
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> Input: grid = [[0,1,3,2],[5,1,2,5],[4,3,8,6]]
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>
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> Output: 7
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Example 2:
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> Input: grid = [[0,2,4],[3,2,1],[1,0,4]]
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>
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> Output: -1
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Constraints:
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- `m == grid.length`
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- `n == grid[i].length`
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- `2 <= m, n <= 1000`
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- `4 <= m * n <= 10^5`
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- `0 <= grid[i][j] <= 10^5`
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- `grid[0][0] == 0`
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package com.schmoczer.leetcode._2577
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import org.junit.jupiter.api.BeforeEach
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import kotlin.test.Test
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import kotlin.test.assertEquals
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class MinimumTimeToVisitCellInGridTest {
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private lateinit var sut: MinimumTimeToVisitCellInGrid
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@BeforeEach
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fun setUp() {
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sut = MinimumTimeToVisitCellInGrid()
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}
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@Test
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fun `a 0,1,3,2 | 5,1,2,5 | 4,3,8,6 grid needs a minimum time of 7`() {
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val grid = arrayOf(
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intArrayOf(0, 1, 3, 2),
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intArrayOf(5, 1, 2, 5),
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intArrayOf(4, 3, 8, 6),
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)
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val expected = 7
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val result = sut.minimumTime(grid)
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assertEquals(expected, result)
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}
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@Test
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fun `a 0,2,4 | 3,2,1 | 1,0,4 grid has no path`() {
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val grid = arrayOf(
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intArrayOf(0, 2, 4),
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intArrayOf(3, 2, 1),
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intArrayOf(1, 0, 4),
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)
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val expected = -1
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val result = sut.minimumTime(grid)
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assertEquals(expected, result)
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}
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}

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