chore: add hackerrank solutions

hacker-rank/lonely-integer/main.go

@@ -0,0 +1,77 @@
+package main
+
+import (
+    "bufio"
+    "fmt"
+    "io"
+    "os"
+    "strconv"
+    "strings"
+)
+
+/*
+ * Complete the 'lonelyinteger' function below.
+ *
+ * The function is expected to return an INTEGER.
+ * The function accepts INTEGER_ARRAY a as parameter.
+ */
+
+func lonelyinteger(a []int32) int32 {
+    m := make(map[int32]int8, len(a)/2+1)
+    for _, i := range a {
+        m[i] = m[i]+1
+    }
+    for k,v := range m {
+        if v == 1 {
+            return k
+        }
+    }
+    return 0
+}
+
+func main() {
+    reader := bufio.NewReaderSize(os.Stdin, 16 * 1024 * 1024)
+
+    stdout, err := os.Create(os.Getenv("OUTPUT_PATH"))
+    checkError(err)
+
+    defer stdout.Close()
+
+    writer := bufio.NewWriterSize(stdout, 16 * 1024 * 1024)
+
+    nTemp, err := strconv.ParseInt(strings.TrimSpace(readLine(reader)), 10, 64)
+    checkError(err)
+    n := int32(nTemp)
+
+    aTemp := strings.Split(strings.TrimSpace(readLine(reader)), " ")
+
+    var a []int32
+
+    for i := 0; i < int(n); i++ {
+        aItemTemp, err := strconv.ParseInt(aTemp[i], 10, 64)
+        checkError(err)
+        aItem := int32(aItemTemp)
+        a = append(a, aItem)
+    }
+
+    result := lonelyinteger(a)
+
+    fmt.Fprintf(writer, "%d\n", result)
+
+    writer.Flush()
+}
+
+func readLine(reader *bufio.Reader) string {
+    str, _, err := reader.ReadLine()
+    if err == io.EOF {
+        return ""
+    }
+
+    return strings.TrimRight(string(str), "\r\n")
+}
+
+func checkError(err error) {
+    if err != nil {
+        panic(err)
+    }
+}