451

1 files changed, 54 insertions, 0 deletions

diff --git a/451/main.go b/451/main.go
new file mode 100644
index 0000000..f025ce7
--- /dev/null
+++ b/451/main.go
@@ -0,0 +1,54 @@
+package main
+
+import (
+	"fmt"
+	"sort"
+)
+
+func frequencySort(s string) string {
+	dict := func(s string) map[int]int {
+		dict := make(map[int]int)
+
+		for i := 0; i < len(s); i++ {
+			if _, ok := dict[int(s[i])]; ok {
+				dict[int(s[i])]++
+			} else {
+				dict[int(s[i])] = 1
+			}
+		}
+
+		return dict
+	}(s)
+
+	type kv struct {
+		key int
+		val int
+	}
+
+	var ss []kv
+
+	for k, v := range dict {
+		ss = append(ss, kv{k, v})
+	}
+
+	sort.Slice(ss, func(i, j int) bool {
+		return ss[i].val > ss[j].val
+	})
+
+	bytes := make([]byte, len(s), len(s))
+	counter := 0
+	for _, kv := range ss {
+		for i := 0; i < kv.val; i++ {
+			bytes[counter] = byte(kv.key)
+			counter++
+		}
+	}
+
+	return string(bytes)
+}
+
+func main() {
+	fmt.Println(frequencySort("tree"))
+	fmt.Println(frequencySort("cccaaa"))
+	fmt.Println(frequencySort("Aabb"))
+}