Create 2483-minimum-penalty-for-a-shop.kt

Author: a93a

kotlin/2483-minimum-penalty-for-a-shop.kt

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+// Time O(n) and space O(n) with prefix/suffix sums
+class Solution {
+    fun bestClosingTime(c: String): Int {
+        val n = c.length
+        val prefix = IntArray (n + 1)
+        val postfix = IntArray (n + 1)
+
+        for (i in 1..n) {
+            prefix[i] = prefix[i - 1] + if (c[i - 1] == 'N') 1 else 0
+        }
+
+        for (i in n - 1 downTo 0) {
+            postfix[i] = postfix[i + 1] + if (c[i] == 'Y') 1 else 0
+        }
+
+        var res = Integer.MAX_VALUE
+        var min = Integer.MAX_VALUE
+        for (i in 0..n) {
+            val pen = prefix[i] + postfix[i]
+            if (pen < min) {
+                min = pen
+                res = i
+            }
+        }
+
+        return res
+    }
+}
+
+// Time O(n) and space O(1) with Kadane's Algorithm
+class Solution {
+    fun bestClosingTime(customers: String): Int {
+        var cur = 0
+        var max = 0
+        var closeTime = 0
+
+        for ((i, c) in customers.withIndex()) {
+            cur += if(c == 'Y') 1 else -1
+            if (cur > max) {
+                max = cur
+                closeTime = i + 1
+            }
+        }
+
+        return closeTime
+    }
+}