Added tasks 3340-3343

src/main/kotlin/g3301_3400/s3340_check_balanced_string/Solution.kt

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+package g3301_3400.s3340_check_balanced_string
+
+// #Easy #String #2024_11_05_Time_1_ms_(100.00%)_Space_34.9_MB_(84.38%)
+
+class Solution {
+    fun isBalanced(num: String): Boolean {
+        var diff = 0
+        var sign = 1
+        val n = num.length
+        for (i in 0 until n) {
+            diff += sign * (num[i].code - '0'.code)
+            sign = -sign
+        }
+        return diff == 0
+    }
+}

src/main/kotlin/g3301_3400/s3340_check_balanced_string/readme.md

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+3340\. Check Balanced String
+
+Easy
+
+You are given a string `num` consisting of only digits. A string of digits is called **balanced** if the sum of the digits at even indices is equal to the sum of digits at odd indices.
+
+Return `true` if `num` is **balanced**, otherwise return `false`.
+
+**Example 1:**
+
+**Input:** num = "1234"
+
+**Output:** false
+
+**Explanation:**
+
+*   The sum of digits at even indices is `1 + 3 == 4`, and the sum of digits at odd indices is `2 + 4 == 6`.
+*   Since 4 is not equal to 6, `num` is not balanced.
+
+**Example 2:**
+
+**Input:** num = "24123"
+
+**Output:** true
+
+**Explanation:**
+
+*   The sum of digits at even indices is `2 + 1 + 3 == 6`, and the sum of digits at odd indices is `4 + 2 == 6`.
+*   Since both are equal the `num` is balanced.
+
+**Constraints:**
+
+*   `2 <= num.length <= 100`
+*   `num` consists of digits only

src/main/kotlin/g3301_3400/s3341_find_minimum_time_to_reach_last_room_i/Solution.kt

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+package g3301_3400.s3341_find_minimum_time_to_reach_last_room_i
+
+// #Medium #Array #Matrix #Heap_Priority_Queue #Graph #Shortest_Path
+// #2024_11_05_Time_257_ms_(42.10%)_Space_46.1_MB_(10.53%)
+
+import java.util.Comparator
+import java.util.PriorityQueue
+import java.util.function.ToIntFunction
+import kotlin.math.max
+
+class Solution {
+    fun minTimeToReach(moveTime: Array<IntArray>): Int {
+        val rows = moveTime.size
+        val cols = moveTime[0].size
+        val minHeap =
+            PriorityQueue<IntArray>(Comparator.comparingInt<IntArray>(ToIntFunction { a: IntArray -> a[0] }))
+        val time: Array<IntArray> = Array<IntArray>(rows) { IntArray(cols) }
+        for (row in time) {
+            row.fill(Int.Companion.MAX_VALUE)
+        }
+        minHeap.offer(intArrayOf(0, 0, 0))
+        time[0][0] = 0
+        val directions = arrayOf<IntArray>(intArrayOf(1, 0), intArrayOf(-1, 0), intArrayOf(0, 1), intArrayOf(0, -1))
+        while (minHeap.isNotEmpty()) {
+            val current = minHeap.poll()
+            val currentTime = current[0]
+            val x = current[1]
+            val y = current[2]
+            if (x == rows - 1 && y == cols - 1) {
+                return currentTime
+            }
+            for (dir in directions) {
+                val newX = x + dir[0]
+                val newY = y + dir[1]
+                if (newX >= 0 && newX < rows && newY >= 0 && newY < cols) {
+                    val waitTime: Int = max((moveTime[newX][newY] - currentTime), 0)
+                    val newTime = currentTime + 1 + waitTime
+                    if (newTime < time[newX][newY]) {
+                        time[newX][newY] = newTime
+                        minHeap.offer(intArrayOf(newTime, newX, newY))
+                    }
+                }
+            }
+        }
+        return -1
+    }
+}

src/main/kotlin/g3301_3400/s3341_find_minimum_time_to_reach_last_room_i/readme.md

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+3341\. Find Minimum Time to Reach Last Room I
+
+Medium
+
+There is a dungeon with `n x m` rooms arranged as a grid.
+
+You are given a 2D array `moveTime` of size `n x m`, where `moveTime[i][j]` represents the **minimum** time in seconds when you can **start moving** to that room. You start from the room `(0, 0)` at time `t = 0` and can move to an **adjacent** room. Moving between adjacent rooms takes _exactly_ one second.
+
+Return the **minimum** time to reach the room `(n - 1, m - 1)`.
+
+Two rooms are **adjacent** if they share a common wall, either _horizontally_ or _vertically_.
+
+**Example 1:**
+
+**Input:** moveTime = [[0,4],[4,4]]
+
+**Output:** 6
+
+**Explanation:**
+
+The minimum time required is 6 seconds.
+
+*   At time `t == 4`, move from room `(0, 0)` to room `(1, 0)` in one second.
+*   At time `t == 5`, move from room `(1, 0)` to room `(1, 1)` in one second.
+
+**Example 2:**
+
+**Input:** moveTime = [[0,0,0],[0,0,0]]
+
+**Output:** 3
+
+**Explanation:**
+
+The minimum time required is 3 seconds.
+
+*   At time `t == 0`, move from room `(0, 0)` to room `(1, 0)` in one second.
+*   At time `t == 1`, move from room `(1, 0)` to room `(1, 1)` in one second.
+*   At time `t == 2`, move from room `(1, 1)` to room `(1, 2)` in one second.
+
+**Example 3:**
+
+**Input:** moveTime = [[0,1],[1,2]]
+
+**Output:** 3
+
+**Constraints:**
+
+*   `2 <= n == moveTime.length <= 50`
+*   `2 <= m == moveTime[i].length <= 50`
+*   <code>0 <= moveTime[i][j] <= 10<sup>9</sup></code>

src/main/kotlin/g3301_3400/s3342_find_minimum_time_to_reach_last_room_ii/Solution.kt

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+package g3301_3400.s3342_find_minimum_time_to_reach_last_room_ii
+
+// #Medium #Array #Matrix #Heap_Priority_Queue #Graph #Shortest_Path
+// #2024_11_05_Time_122_ms_(100.00%)_Space_136.2_MB_(72.73%)
+
+import java.util.Comparator
+import java.util.PriorityQueue
+import kotlin.math.max
+
+class Solution {
+    private class Node {
+        var x: Int = 0
+        var y: Int = 0
+        var t: Int = 0
+        var turn: Int = 0
+    }
+
+    private val dir = arrayOf<IntArray?>(intArrayOf(1, 0), intArrayOf(-1, 0), intArrayOf(0, 1), intArrayOf(0, -1))
+
+    fun minTimeToReach(moveTime: Array<IntArray>): Int {
+        val pq = PriorityQueue<Node>(Comparator { a: Node, b: Node -> a.t - b.t })
+        val m = moveTime.size
+        val n = moveTime[0].size
+        val node = Node()
+        node.x = 0
+        node.y = 0
+        var t = 0
+        node.t = t
+        node.turn = 0
+        pq.add(node)
+        moveTime[0][0] = -1
+        while (pq.isNotEmpty()) {
+            val curr = pq.poll()
+            for (i in 0..3) {
+                val x = curr.x + dir[i]!![0]
+                val y = curr.y + dir[i]!![1]
+                if (x == m - 1 && y == n - 1) {
+                    t = max(curr.t, moveTime[x][y]) + 1 + curr.turn
+                    return t
+                }
+                if (x >= 0 && x < m && y < n && y >= 0 && moveTime[x][y] != -1) {
+                    val newNode = Node()
+                    t = max(curr.t, moveTime[x][y]) + 1 + curr.turn
+                    newNode.x = x
+                    newNode.y = y
+                    newNode.t = t
+                    newNode.turn = if (curr.turn == 1) 0 else 1
+                    pq.add(newNode)
+                    moveTime[x][y] = -1
+                }
+            }
+        }
+        return -1
+    }
+}

src/main/kotlin/g3301_3400/s3342_find_minimum_time_to_reach_last_room_ii/readme.md

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+3342\. Find Minimum Time to Reach Last Room II
+
+Medium
+
+There is a dungeon with `n x m` rooms arranged as a grid.
+
+You are given a 2D array `moveTime` of size `n x m`, where `moveTime[i][j]` represents the **minimum** time in seconds when you can **start moving** to that room. You start from the room `(0, 0)` at time `t = 0` and can move to an **adjacent** room. Moving between **adjacent** rooms takes one second for one move and two seconds for the next, **alternating** between the two.
+
+Return the **minimum** time to reach the room `(n - 1, m - 1)`.
+
+Two rooms are **adjacent** if they share a common wall, either _horizontally_ or _vertically_.
+
+**Example 1:**
+
+**Input:** moveTime = [[0,4],[4,4]]
+
+**Output:** 7
+
+**Explanation:**
+
+The minimum time required is 7 seconds.
+
+*   At time `t == 4`, move from room `(0, 0)` to room `(1, 0)` in one second.
+*   At time `t == 5`, move from room `(1, 0)` to room `(1, 1)` in two seconds.
+
+**Example 2:**
+
+**Input:** moveTime = [[0,0,0,0],[0,0,0,0]]
+
+**Output:** 6
+
+**Explanation:**
+
+The minimum time required is 6 seconds.
+
+*   At time `t == 0`, move from room `(0, 0)` to room `(1, 0)` in one second.
+*   At time `t == 1`, move from room `(1, 0)` to room `(1, 1)` in two seconds.
+*   At time `t == 3`, move from room `(1, 1)` to room `(1, 2)` in one second.
+*   At time `t == 4`, move from room `(1, 2)` to room `(1, 3)` in two seconds.
+
+**Example 3:**
+
+**Input:** moveTime = [[0,1],[1,2]]
+
+**Output:** 4
+
+**Constraints:**
+
+*   `2 <= n == moveTime.length <= 750`
+*   `2 <= m == moveTime[i].length <= 750`
+*   <code>0 <= moveTime[i][j] <= 10<sup>9</sup></code>

src/main/kotlin/g3301_3400/s3343_count_number_of_balanced_permutations/Solution.kt

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+package g3301_3400.s3343_count_number_of_balanced_permutations
+
+// #Hard #String #Dynamic_Programming #Math #Combinatorics
+// #2024_11_05_Time_66_ms_(100.00%)_Space_38.1_MB_(100.00%)
+
+class Solution {
+    fun countBalancedPermutations(num: String): Int {
+        val l = num.length
+        var ts = 0
+        val c = IntArray(10)
+        for (d in num.toCharArray()) {
+            c[d.code - '0'.code]++
+            ts += d.code - '0'.code
+        }
+        if (ts % 2 != 0) {
+            return 0
+        }
+        val hs = ts / 2
+        val m = (l + 1) / 2
+        val f = LongArray(l + 1)
+        f[0] = 1
+        for (i in 1..l) {
+            f[i] = f[i - 1] * i % M
+        }
+        val invF = LongArray(l + 1)
+        invF[l] = modInverse(f[l], M)
+        for (i in l - 1 downTo 0) {
+            invF[i] = invF[i + 1] * (i + 1) % M
+        }
+        val dp = Array<LongArray?>(m + 1) { LongArray(hs + 1) }
+        dp[0]!![0] = 1
+        for (d in 0..9) {
+            if (c[d] == 0) {
+                continue
+            }
+            for (k in m downTo 0) {
+                for (s in hs downTo 0) {
+                    if (dp[k]!![s] == 0L) {
+                        continue
+                    }
+                    var t = 1
+                    while (t <= c[d] && k + t <= m && s + d * t <= hs) {
+                        dp[k + t]!![s + d * t] =
+                            (
+                            dp[k + t]!![s + d * t] + dp[k]!![s] * comb(
+                                c[d],
+                                t,
+                                f,
+                                invF,
+                                M
+                            )
+                            ) % M
+                        t++
+                    }
+                }
+            }
+        }
+        val w = dp[m]!![hs]
+        var r: Long = f[m] * f[l - m] % M
+        for (d in 0..9) {
+            r = r * invF[c[d]] % M
+        }
+        r = r * w % M
+        return r.toInt()
+    }
+
+    private fun modInverse(a: Long, m: Int): Long {
+        var r: Long = 1
+        var p = m - 2L
+        var b = a
+        while (p > 0) {
+            if ((p and 1L) == 1L) {
+                r = r * b % m
+            }
+            b = b * b % m
+            p = p shr 1
+        }
+        return r
+    }
+
+    private fun comb(n: Int, k: Int, f: LongArray, invF: LongArray, m: Int): Long {
+        if (k > n) {
+            return 0
+        }
+        return f[n] * invF[k] % m * invF[n - k] % m
+    }
+
+    companion object {
+        private const val M = 1000000007
+    }
+}