initialise

8/input

@@ -0,0 +1,50 @@
+...........V..................b.g.................
+..................................g...............
+.............................c....................
+............T........Z.......P....................
+.x........................VP......................
+..........................PH......................
+.................H.....Z.......g.R................
+......f............T.V....b......A................
+......................P...........................
+.......f..................A.............R.........
+........x..............T.......l..H.....A.c.......
+..k..x..............Z.............................
+........5....S...............0.A..................
+.............N....L...............................
+.f............................T........s.....N....
+..................l..........bH.......tc.R..N.....
+......Z...6......n......l...k.N...0...............
+...........g....S......l.r.................t..s...
+..L................b.......K..t...................
+................5....n........0.............c.....
+.....L......n............................E........
+.k.......L................m.....................Es
+..............St.....5....Rm......................
+............6..5...................3...0..........
+...........k.................W........3...........
+................n......K...E....2S..........3.....
+....................................E....Q........
+..........M.....x...............K.................
+..h.............................1.................
+.6............z..............4...e.........WY....y
+........f............a.......Y..y...s.............
+...h............r.............v....m..............
+.....h.................v....m.....Y.Q.....W3......
+.........................Yq....Q.................7
+.........6..............7.................9.......
+...................X..........y..q.....2..........
+............r..............q.....y...........7.8..
+..B..............M....4............9..............
+...1.......M...X.......CGzp...4..B...2..K.........
+.....................z...v....Q.....8...........9.
+B.......X.F....rM...v...............2...8..D......
+h1..............................7..D.....8....d...
+...............F.....................9D....4....d.
+..........a......p............F.........W.D......d
+.........................G..C...........q.........
+...B..................................C...........
+.........w..........z....p.....................e..
+.a............G....w........p........F........e...
+........a...w.....................................
+........w...............XC.......G................

8/main.go

@@ -0,0 +1,93 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"regexp"
+	"strings"
+)
+
+func findAntennas(layout [][]string, antenna string) [][]int {
+  antenaPositions := [][]int{}
+  for i := range layout {
+    for j := range layout[i] {
+      if layout[i][j] == antenna {
+        antenaPositions = append(antenaPositions, []int{i,j})
+      }
+    }
+  }  
+  return antenaPositions
+}
+
+func calcAntiNodes(layout [][]string, node1, node2 []int) [][]int {
+  x := node1[0] - node2[0]
+  y := node1[1] - node2[1]
+  antinodes := [][]int{}
+  for i:=0;i<len(layout);i++ {
+    antinode1 := []int{node1[0] + i*x, node1[1] + i*y}
+    antinode2 := []int{node2[0] - i*x, node2[1] - i*y}
+    if ! (antinode1[0] >= 0 && antinode1[1] >= 0 && antinode1[0] < len(layout) && antinode1[1] < len(layout)) {
+      antinode1 = []int{}
+    }
+    if ! (antinode2[0] >= 0 && antinode2[1] >= 0 && antinode2[0] < len(layout) && antinode2[1] < len(layout)) {
+      antinode2 = []int{}
+    }
+    if len(antinode1) > 0 {
+      antinodes = append(antinodes, antinode1)
+    }
+    if len(antinode2) >0 {
+      antinodes = append(antinodes, antinode2)
+    }
+  }
+  return antinodes 
+}
+
+func main() {
+//  file, _ := os.Open("test")
+  file, _ := os.Open("input")
+  defer file.Close()
+  scanner := bufio.NewScanner(file)
+  regexAntenna := regexp.MustCompile(`[^.]`)
+  antennas := []string{}
+  layout := [][]string{}
+  for scanner.Scan() {
+    line := scanner.Text()
+    layout = append(layout, strings.Split(line, ""))
+//    //fmt.Println(line)
+    foundAntennas := regexAntenna.FindAllString(line, -1)
+    if len(foundAntennas) > 0 {
+      antennas = append(antennas, foundAntennas...)
+    }
+  }
+  antennaMap := make(map[string][][]int)
+  for _, antenna := range antennas {
+//    //fmt.Println(antenna)
+    key := antenna
+    antennaMap[key] = findAntennas(layout,antenna)
+  }
+  //fmt.Println(antennaMap)
+  antinodelist := [][]int{}
+  for _,v := range antennaMap {
+    //fmt.Println("key: ", k, "value: ", v)
+    for i:=0;i<len(v);i++ {
+      for j:=0;j<len(v);j++ {
+        if j>i { 
+         //fmt.Println(v[i],v[j])
+         antinodes := calcAntiNodes(layout, v[i], v[j])
+         antinodelist = append(antinodelist, antinodes...)
+        }
+      }
+    }
+  }
+  //fmt.Println(antinodelist)
+  antinodeMap := make(map[[2]int]int)
+  for i := range antinodelist {
+    if len(antinodelist[i]) > 0 {
+      key := [2]int{antinodelist[i][0], antinodelist[i][1]}
+      antinodeMap[key]++
+    }
+  }
+  fmt.Println(len(antinodeMap))
+}
+

8/test

@@ -0,0 +1,12 @@
+............
+........0...
+.....0......
+.......0....
+....0.......
+......A.....
+............
+............
+........A...
+.........A..
+............
+............