package main import ( "bufio" "fmt" "os" "sort" "strconv" ) func configure(scanner *bufio.Scanner) { scanner.Split(bufio.ScanWords) scanner.Buffer(make([]byte, 1000005), 1000005) } func getNextString(scanner *bufio.Scanner) string { scanned := scanner.Scan() if !scanned { panic("scan failed") } return scanner.Text() } func getNextInt(scanner *bufio.Scanner) int { i, _ := strconv.Atoi(getNextString(scanner)) return i } func getNextInt64(scanner *bufio.Scanner) int64 { i, _ := strconv.ParseInt(getNextString(scanner), 10, 64) return i } func getNextFloat64(scanner *bufio.Scanner) float64 { i, _ := strconv.ParseFloat(getNextString(scanner), 64) return i } func main() { fp := os.Stdin wfp := os.Stdout extra := 0 if os.Getenv("I") == "IronMan" { fp, _ = os.Open(os.Getenv("END_GAME")) extra = 100 } scanner := bufio.NewScanner(fp) configure(scanner) writer := bufio.NewWriter(wfp) defer func() { r := recover() if r != nil { fmt.Fprintln(writer, r) } writer.Flush() }() solve(scanner, writer) for i := 0; i < extra; i++ { fmt.Fprintln(writer, "-----------------------------------") solve(scanner, writer) } } func solve(scanner *bufio.Scanner, writer *bufio.Writer) { n := getNextInt(scanner) x := getNextInt64(scanner) aa := make([]int64, n) for i := 0; i < n; i++ { aa[i] = getNextInt64(scanner) } sort.SliceStable(aa, func(i, j int) bool { return aa[i] < aa[j] }) var ans int for i := 0; i < n; i++ { l := lower(i, x, aa) r := lower(i, x+1, aa) ans += r - l } fmt.Fprintln(writer, ans) } func lower(i int, x int64, ss []int64) int { l := -1 r := len(ss) for l+1 < r { m := (l + r) >> 1 if x > ss[m]+ss[i] { l = m continue } r = m } return r }