diff --git a/leetcode_java/src/main/java/LeetCodeJava/String/FindAndReplaceInString.java b/leetcode_java/src/main/java/LeetCodeJava/String/FindAndReplaceInString.java
index e5a2f3e3..84f3181b 100644
--- a/leetcode_java/src/main/java/LeetCodeJava/String/FindAndReplaceInString.java
+++ b/leetcode_java/src/main/java/LeetCodeJava/String/FindAndReplaceInString.java
@@ -105,6 +105,8 @@ public String findReplaceString_0_1(String s, int[] indices, String[] sources, S
                  *
                  *   update index with replacement string length
                  *
+                 *   -> NOTE !!! we use "source" length (with replacementIndex)
+                 *               (but NOT target length)
                  */
                 i += sources[replacementIndex].length(); // Skip the replaced substring
             } else {