From 804014f9e58cbaacb41a06a59c899413f72e7b60 Mon Sep 17 00:00:00 2001
From: "exercism-solutions-syncer[bot]"
 <211797793+exercism-solutions-syncer[bot]@users.noreply.github.com>
Date: Wed, 21 Jan 2026 20:30:20 +0000
Subject: [PATCH] [Sync Iteration] go/parallel-letter-frequency/1

---
 .../1/parallel_letter_frequency.go            | 41 +++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 solutions/go/parallel-letter-frequency/1/parallel_letter_frequency.go

diff --git a/solutions/go/parallel-letter-frequency/1/parallel_letter_frequency.go b/solutions/go/parallel-letter-frequency/1/parallel_letter_frequency.go
new file mode 100644
index 0000000..bb0bac4
--- /dev/null
+++ b/solutions/go/parallel-letter-frequency/1/parallel_letter_frequency.go
@@ -0,0 +1,41 @@
+package letter
+
+import "sync"
+
+// FreqMap records the frequency of each rune in a given text.
+type FreqMap map[rune]int
+
+// Frequency counts the frequency of each rune in a given text and returns this
+// data as a FreqMap.
+func Frequency(text string) FreqMap {
+	frequencies := FreqMap{}
+	for _, r := range text {
+		frequencies[r]++
+	}
+	return frequencies
+}
+
+// ConcurrentFrequency counts the frequency of each rune in the given strings,
+// by making use of concurrency.
+func ConcurrentFrequency(texts []string) FreqMap {
+	var wg sync.WaitGroup
+	var mu sync.Mutex
+
+	m := make(FreqMap)
+	for _, line := range texts {
+		wg.Add(1)
+		go func(line string) {
+			defer wg.Done()
+
+			for _, r := range line {
+				mu.Lock()
+				m[r]++
+				mu.Unlock()
+			}
+		}(line)
+	}
+
+	wg.Wait()
+
+	return m
+}