Improved tasks 815, 823, 828

Author: javadev

src/main/kotlin/g0801_0900/s0815_bus_routes/Solution.kt

@@ -3,7 +3,6 @@ package g0801_0900.s0815_bus_routes
 // #Hard #Array #Hash_Table #Breadth_First_Search #Level_2_Day_11_Graph/BFS/DFS
 // #2023_03_22_Time_429_ms_(100.00%)_Space_55.8_MB_(100.00%)
 
-import java.util.Arrays
 import java.util.LinkedList
 import java.util.Queue
 import kotlin.collections.ArrayList
@@ -53,14 +52,14 @@ class Solution {
         val len = routes.size
         val graph: Array<ArrayList<Int>?> = arrayOfNulls(len)
         for (i in 0 until len) {
-            Arrays.sort(routes[i])
+            routes[i].sort()
             graph[i] = ArrayList()
-            var id = Arrays.binarySearch(routes[i], source)
+            var id = routes[i].binarySearch(source)
             if (id >= 0) {
                 queue.offer(i)
                 taken[i] = true
             }
-            id = Arrays.binarySearch(routes[i], target)
+            id = routes[i].binarySearch(target)
             if (id >= 0) {
                 targetRoutes.add(i)
             }

src/main/kotlin/g0801_0900/s0823_binary_trees_with_factors/Solution.kt

@@ -3,13 +3,11 @@ package g0801_0900.s0823_binary_trees_with_factors
 // #Medium #Array #Hash_Table #Dynamic_Programming
 // #2023_03_25_Time_298_ms_(100.00%)_Space_45.1_MB_(100.00%)dsecx
 
-import java.util.Arrays
-
 class Solution {
     private val dp: MutableMap<Int, Long> = HashMap()
     private val nums: MutableMap<Int, Int> = HashMap()
     fun numFactoredBinaryTrees(arr: IntArray): Int {
-        Arrays.sort(arr)
+        arr.sort()
         for (i in arr.indices) {
             nums[arr[i]] = i
         }

src/main/kotlin/g0801_0900/s0828_count_unique_characters_of_all_substrings_of_a_given_string/Solution.kt

@@ -3,17 +3,15 @@ package g0801_0900.s0828_count_unique_characters_of_all_substrings_of_a_given_st
 // #Hard #String #Hash_Table #Dynamic_Programming
 // #2023_03_25_Time_216_ms_(100.00%)_Space_37.1_MB_(50.00%)
 
-import java.util.Arrays
-
 class Solution {
     fun uniqueLetterString(s: String): Int {
         // Store last index of a character.
         val lastCharIdx = IntArray(26)
         // Store last to last index of a character.
         // Eg. For ABA - lastCharIdx = 2, prevLastCharIdx = 0.
         val prevLastCharIdx = IntArray(26)
-        Arrays.fill(lastCharIdx, -1)
-        Arrays.fill(prevLastCharIdx, -1)
+        lastCharIdx.fill(-1)
+        prevLastCharIdx.fill(-1)
         val len = s.length
         val dp = IntArray(len)
         var account = 1