{{ message }}

Instantly share code, notes, and snippets.

# yosu/celebrity.go

Last active Feb 3, 2016
5.5 Celebrity Problem - Introduction to Algorithms by Udi Manber
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters
 package main import ( "bufio" "flag" "fmt" "os" "strconv" "strings" ) type Reader struct { *bufio.Scanner } func NewReader() *Reader { scanner := bufio.NewScanner(os.Stdin) return &Reader{scanner} } func (r *Reader) scanInt() int { r.Scan() n, _ := strconv.Atoi(r.Text()) return n } func (r *Reader) scanIntArray() []int { text := r.scanText() strs := strings.Split(text, " ") ints := make([]int, len(strs)) for i, v := range strs { ints[i], _ = strconv.Atoi(v) } return ints } func (r *Reader) scanText() string { r.Scan() return r.Text() } func main() { r := NewReader() n := r.scanInt() m := [][]int{} for i := 0; i < n; i++ { m = append(m, r.scanIntArray()) } var algorithm = flag.Int("algorithm", 1, "select algorithm type: 1 - simple, 2 - fine") flag.Parse() fmt.Fprintf(os.Stderr, "Algorithm: %d\n", *algorithm) celeb := findCelebrity(m, *algorithm) if celeb != -1 { fmt.Printf("%d\n", celeb+1) } else { fmt.Println("no celeb") } } func knownByAll(m [][]int, j int) bool { for i := 0; i < len(m); i++ { if m[i][j] == 0 && i != j { return false } } return true } func knowAny(m [][]int, i int) bool { for j := 0; j < len(m); j++ { if m[i][j] == 1 && i != j { return true } } return false } func findCandidate(m [][]int) int { i := 0 j := 1 next := 2 n := len(m) for next <= n { if m[i][j] == 1 { i = next } else { j = next } next = next + 1 } if i == n { return j } return i } func findCelebrity(m [][]int, algorithm int) int { if algorithm == 1 { return findCelebrity1(m) } return findCelebrity2(m) } func findCelebrity1(m [][]int) int { for i := 0; i < len(m); i++ { if !knowAny(m, i) && knownByAll(m, i) { return i } } return -1 } func findCelebrity2(m [][]int) int { c := findCandidate(m) if knownByAll(m, c) && !knowAny(m, c) { return c } return -1 }
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters
 5 0 0 1 0 0 1 0 1 0 0 0 0 0 0 0 1 0 1 0 0 1 1 1 1 0
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters
 5 0 0 1 0 0 1 0 1 0 0 0 0 0 1 0 1 0 1 0 0 1 1 1 1 0