From 4498347c2d50e96290b002f6593ae55d26dd4398 Mon Sep 17 00:00:00 2001
From: Sergei Kozelko <kozelkos@yandex.ru>
Date: Wed, 11 Aug 2021 19:06:49 +0300
Subject: [PATCH] Make faster duplicate keys checking

---
 src/commonMain/kotlin/com/charleskorn/kaml/YamlNode.kt | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/commonMain/kotlin/com/charleskorn/kaml/YamlNode.kt b/src/commonMain/kotlin/com/charleskorn/kaml/YamlNode.kt
index 71ac20e4..1a29be92 100644
--- a/src/commonMain/kotlin/com/charleskorn/kaml/YamlNode.kt
+++ b/src/commonMain/kotlin/com/charleskorn/kaml/YamlNode.kt
@@ -154,12 +154,15 @@ public data class YamlMap(val entries: Map<YamlScalar, YamlNode>, override val p
             }
         }
 
-        keys.forEachIndexed { index, key ->
-            val duplicate = keys.subList(0, index).firstOrNull { it.equivalentContentTo(key) }
+        val encounteredKeys = mutableMapOf<String, YamlScalar>()
+        keys.forEach { key ->
+            val duplicate = encounteredKeys[key.content]
 
             if (duplicate != null) {
                 throw DuplicateKeyException(duplicate.path, key.path, key.contentToString())
             }
+
+            encounteredKeys[key.content] = key
         }
     }