Create 2864-maximum-odd-binary-number.kt

Author: a93a

kotlin/2864-maximum-odd-binary-number.kt

@@ -0,0 +1,49 @@
+// traverse and swap indices
+class Solution {
+    fun maximumOddBinaryNumber(s: String): String {
+        val sArr = s.toCharArray()
+        var left = 0
+
+        for (i in 0 until sArr.size) {
+            if (sArr[i] == '1') {
+                sArr[i] = sArr[left].also { sArr[left] = sArr[i] }
+                left++
+            }
+        }
+
+        sArr[left - 1] = sArr[sArr.lastIndex].also { sArr[sArr.lastIndex] = sArr[left - 1] }
+        return sArr.joinToString("")
+    }
+}
+
+// Count 1's and build at once
+class Solution {
+    fun maximumOddBinaryNumber(s: String): String {
+        var count = 0
+        for (c in s) {
+            if (c == '1') count++
+        }
+
+        return "1".repeat(count - 1) + "0".repeat(s.length - count) + "1"
+    }
+}
+
+// Rolling string builder
+class Solution {
+    fun maximumOddBinaryNumber(s: String) = buildString {
+        var count = s.count  { it == '1' } - 1
+        val n = s.length
+
+        for (i in 0 until n - 1) {
+            if (count > 0) {
+                append("1")
+                count--
+            } else {
+                append("0")
+            }
+        }
+
+        append("1")
+        return toString()
+    }
+}