Added tasks 3731-3734

src/main/kotlin/g3701_3800/s3731_find_missing_elements/Solution.kt

@@ -0,0 +1,29 @@
+package g3701_3800.s3731_find_missing_elements
+
+// #Easy #Array #Hash_Table #Sorting #Weekly_Contest_474
+// #2025_11_05_Time_2_ms_(100.00%)_Space_46.48_MB_(84.44%)
+
+class Solution {
+    fun findMissingElements(nums: IntArray): List<Int> {
+        var maxi = 0
+        var mini = 101
+        val list: MutableList<Int> = ArrayList()
+        val array = BooleanArray(101)
+        for (num in nums) {
+            array[num] = true
+            if (maxi < num) {
+                maxi = num
+            }
+            if (mini > num) {
+                mini = num
+            }
+        }
+        for (index in mini + 1..<maxi) {
+            if (array[index]) {
+                continue
+            }
+            list.add(index)
+        }
+        return list
+    }
+}

src/main/kotlin/g3701_3800/s3731_find_missing_elements/readme.md

@@ -0,0 +1,46 @@
+3731\. Find Missing Elements
+
+Easy
+
+You are given an integer array `nums` consisting of **unique** integers.
+
+Originally, `nums` contained **every integer** within a certain range. However, some integers might have gone **missing** from the array.
+
+The **smallest** and **largest** integers of the original range are still present in `nums`.
+
+Return a **sorted** list of all the missing integers in this range. If no integers are missing, return an **empty** list.
+
+**Example 1:**
+
+**Input:** nums = [1,4,2,5]
+
+**Output:** [3]
+
+**Explanation:**
+
+The smallest integer is 1 and the largest is 5, so the full range should be `[1,2,3,4,5]`. Among these, only 3 is missing.
+
+**Example 2:**
+
+**Input:** nums = [7,8,6,9]
+
+**Output:** []
+
+**Explanation:**
+
+The smallest integer is 6 and the largest is 9, so the full range is `[6,7,8,9]`. All integers are already present, so no integer is missing.
+
+**Example 3:**
+
+**Input:** nums = [5,1]
+
+**Output:** [2,3,4]
+
+**Explanation:**
+
+The smallest integer is 1 and the largest is 5, so the full range should be `[1,2,3,4,5]`. The missing integers are 2, 3, and 4.
+
+**Constraints:**
+
+*   `2 <= nums.length <= 100`
+*   `1 <= nums[i] <= 100`

src/main/kotlin/g3701_3800/s3732_maximum_product_of_three_elements_after_one_replacement/Solution.kt

@@ -0,0 +1,23 @@
+package g3701_3800.s3732_maximum_product_of_three_elements_after_one_replacement
+
+// #Medium #Array #Math #Sorting #Greedy #Weekly_Contest_474
+// #2025_11_05_Time_6_ms_(88.00%)_Space_74.51_MB_(84.00%)
+
+import kotlin.math.abs
+
+class Solution {
+    fun maxProduct(nums: IntArray): Long {
+        var a: Long = 0
+        var b: Long = 0
+        for (x in nums) {
+            val ax = abs(x).toLong()
+            if (ax >= a) {
+                b = a
+                a = ax
+            } else if (ax > b) {
+                b = ax
+            }
+        }
+        return 100000L * a * b
+    }
+}

src/main/kotlin/g3701_3800/s3732_maximum_product_of_three_elements_after_one_replacement/readme.md

@@ -0,0 +1,51 @@
+3732\. Maximum Product of Three Elements After One Replacement
+
+Medium
+
+You are given an integer array `nums`.
+
+You **must** replace **exactly one** element in the array with **any** integer value in the range <code>[-10<sup>5</sup>, 10<sup>5</sup>]</code> (inclusive).
+
+After performing this single replacement, determine the **maximum possible product** of **any three** elements at **distinct indices** from the modified array.
+
+Return an integer denoting the **maximum product** achievable.
+
+**Example 1:**
+
+**Input:** nums = [-5,7,0]
+
+**Output:** 3500000
+
+**Explanation:**
+
+Replacing 0 with -10<sup>5</sup> gives the array <code>[-5, 7, -10<sup>5</sup>]</code>, which has a product <code>(-5) * 7 * (-10<sup>5</sup>) = 3500000</code>. The maximum product is 3500000.
+
+**Example 2:**
+
+**Input:** nums = [-4,-2,-1,-3]
+
+**Output:** 1200000
+
+**Explanation:**
+
+Two ways to achieve the maximum product include:
+
+*   `[-4, -2, -3]` → replace -2 with 10<sup>5</sup> → product = <code>(-4) * 10<sup>5</sup> * (-3) = 1200000</code>.
+*   `[-4, -1, -3]` → replace -1 with 10<sup>5</sup> → product = <code>(-4) * 10<sup>5</sup> * (-3) = 1200000</code>.
+
+The maximum product is 1200000.
+
+**Example 3:**
+
+**Input:** nums = [0,10,0]
+
+**Output:** 0
+
+**Explanation:**
+
+There is no way to replace an element with another integer and not have a 0 in the array. Hence, the product of all three elements will always be 0, and the maximum product is 0.
+
+**Constraints:**
+
+*   <code>3 <= nums.length <= 10<sup>5</sup></code>
+*   <code>-10<sup>5</sup> <= nums[i] <= 10<sup>5</sup></code>

src/main/kotlin/g3701_3800/s3733_minimum_time_to_complete_all_deliveries/Solution.kt

@@ -0,0 +1,49 @@
+package g3701_3800.s3733_minimum_time_to_complete_all_deliveries
+
+// #Medium #Math #Binary_Search #Weekly_Contest_474
+// #2025_11_05_Time_2_ms_(100.00%)_Space_42.47_MB_(100.00%)
+
+import kotlin.math.max
+
+class Solution {
+    private fun pos(k: Long, n1: Long, n2: Long, p1: Int, p2: Int, lVal: Long): Boolean {
+        val kP1 = k / p1
+        val kP2 = k / p2
+        val kL = k / lVal
+        val s1 = kP2 - kL
+        val s2 = kP1 - kL
+        val sB = k - kP1 - kP2 + kL
+        val w1 = max(0L, n1 - s1)
+        val w2 = max(0L, n2 - s2)
+        return (w1 + w2) <= sB
+    }
+
+    private fun findGcd(a: Long, b: Long): Long {
+        if (b == 0L) {
+            return a
+        }
+        return findGcd(b, a % b)
+    }
+
+    fun minimumTime(d: IntArray, r: IntArray): Long {
+        val n1 = d[0].toLong()
+        val n2 = d[1].toLong()
+        val p1 = r[0]
+        val p2 = r[1]
+        val g = findGcd(p1.toLong(), p2.toLong())
+        val l = p1.toLong() * p2 / g
+        var lo = n1 + n2
+        var hi = (n1 + n2) * max(p1, p2)
+        var res = hi
+        while (lo <= hi) {
+            val mid = lo + (hi - lo) / 2
+            if (pos(mid, n1, n2, p1, p2, l)) {
+                res = mid
+                hi = mid - 1
+            } else {
+                lo = mid + 1
+            }
+        }
+        return res
+    }
+}

src/main/kotlin/g3701_3800/s3733_minimum_time_to_complete_all_deliveries/readme.md

@@ -0,0 +1,53 @@
+3733\. Minimum Time to Complete All Deliveries
+
+Medium
+
+You are given two integer arrays of size 2: <code>d = [d<sub>1</sub>, d<sub>2</sub>]</code> and <code>r = [r<sub>1</sub>, r<sub>2</sub>]</code>.
+
+Two delivery drones are tasked with completing a specific number of deliveries. Drone `i` must complete <code>d<sub>i</sub></code> deliveries.
+
+Each delivery takes **exactly** one hour and **only one** drone can make a delivery at any given hour.
+
+Additionally, both drones require recharging at specific intervals during which they cannot make deliveries. Drone `i` must recharge every <code>r<sub>i</sub></code> hours (i.e. at hours that are multiples of <code>r<sub>i</sub></code>).
+
+Return an integer denoting the **minimum** total time (in hours) required to complete all deliveries.
+
+**Example 1:**
+
+**Input:** d = [3,1], r = [2,3]
+
+**Output:** 5
+
+**Explanation:**
+
+*   The first drone delivers at hours 1, 3, 5 (recharges at hours 2, 4).
+*   The second drone delivers at hour 2 (recharges at hour 3).
+
+**Example 2:**
+
+**Input:** d = [1,3], r = [2,2]
+
+**Output:** 7
+
+**Explanation:**
+
+*   The first drone delivers at hour 3 (recharges at hours 2, 4, 6).
+*   The second drone delivers at hours 1, 5, 7 (recharges at hours 2, 4, 6).
+
+**Example 3:**
+
+**Input:** d = [2,1], r = [3,4]
+
+**Output:** 3
+
+**Explanation:**
+
+*   The first drone delivers at hours 1, 2 (recharges at hour 3).
+*   The second drone delivers at hour 3.
+
+**Constraints:**
+
+*   <code>d = [d<sub>1</sub>, d<sub>2</sub>]</code>
+*   <code>1 <= d<sub>i</sub> <= 10<sup>9</sup></code>
+*   <code>r = [r<sub>1</sub>, r<sub>2</sub>]</code>
+*   <code>2 <= r<sub>i</sub> <= 3 * 10<sup>4</sup></code>

src/main/kotlin/g3701_3800/s3734_lexicographically_smallest_palindromic_permutation_greater_than_target/Solution.kt

@@ -0,0 +1,94 @@
+package g3701_3800.s3734_lexicographically_smallest_palindromic_permutation_greater_than_target
+
+// #Hard #String #Two_Pointers #Enumeration #Weekly_Contest_474
+// #2025_11_05_Time_4_ms_(100.00%)_Space_46.12_MB_(77.78%)
+
+class Solution {
+    internal fun func(i: Int, target: String, ans: CharArray, l: Int, r: Int, freq: IntArray, end: Boolean): Boolean {
+        if (l > r) {
+            return String(ans).compareTo(target) > 0
+        }
+        if (l == r) {
+            var left = '#'
+            for (k in 0 until 26) {
+                if (freq[k] > 0) {
+                    left = (k + 'a'.code).toChar()
+                }
+            }
+            freq[left.code - 'a'.code]--
+            ans[l] = left
+            if (func(i + 1, target, ans, l + 1, r - 1, freq, end)) {
+                return true
+            }
+            freq[left.code - 'a'.code]++
+            ans[l] = '#'
+            return false
+        }
+        if (end) {
+            for (j in 0 until 26) {
+                if (freq[j] > 1) {
+                    freq[j] -= 2
+                    val charJ = (j + 'a'.code).toChar()
+                    ans[l] = charJ
+                    ans[r] = charJ
+                    if (func(i + 1, target, ans, l + 1, r - 1, freq, end)) {
+                        return true
+                    }
+                    ans[l] = '#'
+                    ans[r] = '#'
+                    freq[j] += 2
+                }
+            }
+            return false
+        }
+        val curr = target[i]
+        var next = '1'
+        for (k in (curr.code - 'a'.code + 1) until 26) {
+            if (freq[k] > 1) {
+                next = (k + 'a'.code).toChar()
+                break
+            }
+        }
+        if (freq[curr.code - 'a'.code] > 1) {
+            ans[l] = curr
+            ans[r] = curr
+            freq[curr.code - 'a'.code] -= 2
+            if (func(i + 1, target, ans, l + 1, r - 1, freq, false)) { // end = false
+                return true
+            }
+            freq[curr.code - 'a'.code] += 2
+        }
+        if (next != '1') {
+            ans[l] = next
+            ans[r] = next
+            freq[next.code - 'a'.code] -= 2
+            if (func(i + 1, target, ans, l + 1, r - 1, freq, true)) { // end = true
+                return true
+            }
+        }
+        ans[l] = '#'
+        ans[r] = '#'
+        return false
+    }
+
+    fun lexPalindromicPermutation(s: String, target: String): String {
+        val freq = IntArray(26)
+        for (char in s) {
+            freq[char.code - 'a'.code]++
+        }
+        var oddc = 0
+        for (i in 0 until 26) {
+            if (freq[i] % 2 == 1) {
+                oddc++
+            }
+        }
+        if (oddc > 1) {
+            return ""
+        }
+        val ans = CharArray(s.length) { '#' }
+        if (func(0, target, ans, 0, s.length - 1, freq, false)) {
+            return String(ans)
+        }
+        return ""
+    }
+}