Create 1963-minimum-number-of-swaps-to-make-the-string-balanced.kt

Author: a93a

kotlin/1963-minimum-number-of-swaps-to-make-the-string-balanced.kt

@@ -0,0 +1,49 @@
+// Same as below, using pointer, but more compact solution, time O(N), space O(1)
+class Solution {
+    fun minSwaps(s: String): Int {
+        var closed = 0
+        for(c in s){
+            if(c == '[') closed++
+            else if (closed > 0) closed--
+        }
+        return (closed + 1) / 2
+    }
+}
+
+// Solution using pointer (since we only have 2 chars to check), time O(N), space O(1)
+class Solution {
+    fun minSwaps(s: String): Int {
+        var mismatches = 0
+        var closed = 0
+        for(c in s){
+            if(c == ']') 
+                if(closed>0)
+                    closed--
+                else
+                    mismatches++
+            else{ 
+                closed++
+            }
+        }
+        return (mismatches + 1) / 2
+    }
+}
+
+// Stack solution, time O(N), space O(N)
+class Solution {
+    fun minSwaps(s: String): Int {
+        val stack = Stack<Char>()
+        var mismatches = 0
+        for(c in s){
+            if(c == ']') 
+                if(!stack.isEmpty())
+                    stack.pop()
+                else
+                    mismatches++
+            else{ 
+                stack.push(c)
+            }
+        }
+        return (mismatches + 1) / 2
+    }
+}