Create 0473-matchsticks-to-square.kt

Author: a93a

kotlin/0473-matchsticks-to-square.kt

@@ -0,0 +1,27 @@
+class Solution {
+    fun makesquare(matchsticks: IntArray): Boolean {
+        val length = matchsticks.sum()!! / 4
+        val sides = IntArray (4)
+
+        if (matchsticks.sum()!! / 4 != length) return false
+
+        matchsticks.sortDescending()
+
+        fun backtrack(i: Int): Boolean {
+            if (i == matchsticks.size) return true
+
+            for (j in 0..3) {
+                if (sides[j] + matchsticks[i] <= length) {
+                    sides[j] += matchsticks[i]
+                    if (backtrack(i + 1))
+                        return true
+                    sides[j] -= matchsticks[i]
+                }
+            }
+
+            return false
+        }
+
+        return backtrack(0)
+    }
+}