fine, I'll put them on github

1/1.go

@@ -0,0 +1,37 @@
+package main
+
+import "os"
+import "fmt"
+import "strings"
+import "strconv"
+
+// go run 1.go <input>
+
+func main() {
+
+	s := strings.Split(os.Args[1], "")
+	checksum := 0
+	checksum2 := 0
+
+	for index, element := range s {
+		pre := index - 1
+		pre2 := (index + (len(s) / 2)) % len(s)
+		if pre == -1 {
+			pre = len(s) - 1
+		}
+
+		fmt.Println(index, element, pre, s[pre])
+
+		if element == s[pre] {
+			i, _ := strconv.Atoi(element)
+			checksum += i
+		}
+		if element == s[pre2] {
+			i, _ := strconv.Atoi(element)
+			checksum2 += i
+		}
+
+	}
+
+	fmt.Println(checksum, checksum2)
+}

2/2.2.go

@@ -0,0 +1,51 @@
+package main
+
+import "os"
+import "fmt"
+import "strings"
+import "strconv"
+import "bufio"
+
+// cat input | go run 2.2.go
+
+func main() {
+
+	scanner := bufio.NewScanner(os.Stdin)
+	checksum := 0
+	for scanner.Scan() {
+
+		s := strings.Split(scanner.Text(), "\t")
+		fmt.Println(s)
+
+		for index, element := range s {
+			fmt.Println(index, element)
+			i, _ := strconv.Atoi(element)
+
+			for index2, e2 := range s {
+
+				i2, _ := strconv.Atoi(e2)
+
+				if index == index2 {
+					continue
+				}
+				if i2 > i {
+					continue
+				}
+
+				result := float64(i) / float64(i2)
+				ir := float64(int(result))
+
+				if result == ir {
+					fmt.Println("yes!", i, i2, result)
+					checksum += int(result)
+				}
+
+			}
+		}
+
+		fmt.Println("---")
+
+	}
+
+	fmt.Println(checksum)
+}

2/2.go

@@ -0,0 +1,41 @@
+package main
+
+import "os"
+import "fmt"
+import "strings"
+import "strconv"
+import "bufio"
+
+// cat input | go run 2.go
+
+func main() {
+
+	scanner := bufio.NewScanner(os.Stdin)
+	checksum := 0
+	for scanner.Scan() {
+
+		min := 9999999999999 // messy, but whatever.
+		max := 0
+		s := strings.Split(scanner.Text(), "\t")
+
+		for index, element := range s {
+			fmt.Println(index, element)
+			i, _ := strconv.Atoi(element)
+			if i < min {
+				min = i
+			}
+			if i > max {
+				max = i
+			}
+		}
+
+		diff := max - min
+		checksum += diff
+		fmt.Println("min", min, "max", max, "diff", diff)
+		fmt.Println("---")
+
+	}
+
+	fmt.Println(checksum)
+
+}

3/3.2.go

@@ -0,0 +1,72 @@
+package main
+
+import "os"
+import "fmt"
+import "math"
+import "strconv"
+
+// go run 3.2.go <input>
+
+// Need to brute force part two anyway, should have done that for part one...
+
+func main() {
+
+	target, _ := strconv.Atoi(os.Args[1])
+
+	// This is way overkill for the real solution, but needed it for testing initial grid size with value = i
+	squareSize := int(math.Ceil(math.Sqrt(float64(target)))) + 2
+	grid := make([][]int, squareSize)
+
+	for i := 0; i < squareSize; i++ {
+		y := make([]int, squareSize)
+		grid[i] = y
+	}
+
+	dirX := 1
+	dirY := 0
+	startVal := 1
+	posX := (squareSize - 1) / 2
+	posY := (squareSize - 1) / 2
+	grid[posX][posY] = 1
+
+	fmt.Println("sq", squareSize, "xy", posX, posY, "dir", dirX, dirY)
+
+	for i := startVal + 1; i <= target; i++ {
+
+		posX += dirX
+		posY += dirY
+
+		adj := grid[posX-1][posY-1] + grid[posX-1][posY] + grid[posX-1][posY+1] +
+			grid[posX][posY-1] + grid[posX][posY+1] +
+			grid[posX+1][posY-1] + grid[posX+1][posY] + grid[posX+1][posY+1]
+
+		//adj = i
+
+		grid[posX][posY] = adj
+		if adj > target {
+			fmt.Println("Result:", adj)
+			os.Exit(0)
+		}
+
+		if dirY == -1 && grid[posX+1][posY] == 0 {
+			dirY = 0
+			dirX = 1
+		}
+		if dirY == 1 && grid[posX-1][posY] == 0 {
+			dirY = 0
+			dirX = -1
+		}
+		if dirX == -1 && grid[posX][posY-1] == 0 {
+			dirY = -1
+			dirX = 0
+		}
+		if dirX == 1 && grid[posX][posY+1] == 0 {
+			dirY = 1
+			dirX = 0
+		}
+
+	}
+
+	//fmt.Println(grid)
+
+}

3/3.go

@@ -0,0 +1,90 @@
+package main
+
+import "fmt"
+import "math"
+import "time"
+import "os"
+import "strconv"
+
+// go run 3.go <input>
+
+/*
+
+"Debugging is twice as hard as writing the code in the first place.
+ Therefore, if you write the code as cleverly as possible, you are,
+ by definition, not smart enough to debug it." -- Brian W. Kernighan
+
+I probably should have just brute forced this, it took me ages to track
+down the off-by-one error I had for even squares *some* of the time...
+
+*/
+
+func main() {
+
+	start := time.Now()
+
+	target, _ := strconv.Atoi(os.Args[1])
+	squareSize := int(math.Ceil(math.Sqrt(float64(target))))
+	startVal := (squareSize-1)*(squareSize-1) + 1
+
+	dirX := 0
+	dirY := 0
+	min := 0
+	max := 0
+	posX := 0
+	posY := 0
+
+	if (squareSize % 2) == 1 {
+		min = -1 * (squareSize - 1) / 2
+		max = (squareSize - 1) / 2
+		dirX = 0
+		dirY = -1
+		posX = min
+		posY = max
+
+		fmt.Println("odd", squareSize)
+		fmt.Println("start:", startVal, "min:", min, "max:", max)
+
+	} else {
+		min = (-1 * (squareSize) / 2) + 1
+		max = (squareSize) / 2
+		dirX = 0
+		dirY = 1
+		posX = max
+		posY = min
+
+		fmt.Println("even", squareSize)
+		fmt.Println("start:", startVal, "min:", min, "max:", max)
+
+	}
+
+	for i := startVal; i < target; i++ {
+		fmt.Println(i, posX, posY)
+
+		if dirY == -1 && posY == min {
+			dirY = 0
+			dirX = 1
+		}
+		if dirY == 1 && posY == max {
+			dirY = 0
+			dirX = -1
+		}
+		if dirX == -1 && posX == min {
+			dirY = -1
+			dirX = 0
+		}
+		if dirX == 1 && posX == max {
+			dirY = 1
+			dirX = 0
+		}
+
+		posX += dirX
+		posY += dirY
+	}
+
+	fmt.Println("result:", posX, posY, (math.Abs(float64(posX)) + math.Abs(float64(posY))))
+
+	t := time.Now()
+	elapsed := t.Sub(start)
+	fmt.Println(elapsed, "ms")
+}

4/4.2.go

@@ -0,0 +1,43 @@
+package main
+
+import "os"
+import "fmt"
+import "strings"
+import "bufio"
+import "sort"
+
+// cat input | go run 4.2.go
+
+func main() {
+
+	failed := 0
+	count := 0
+
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		count++
+		s := strings.Split(scanner.Text(), " ")
+		fmt.Println(s)
+
+		for i := 0; i < len(s); i++ {
+			an := strings.Split(s[i], "")
+			sort.Strings(an)
+			san := strings.Join(an, "")
+			s[i] = san
+		}
+
+		sort.Strings(s)
+
+		for i := 1; i < len(s); i++ {
+			fmt.Println(i, s[i])
+			if s[i] == s[i-1] {
+				failed++
+				fmt.Println("Failed!", s[i], s[i-1])
+				break
+			}
+		}
+
+		fmt.Println("---")
+	}
+	fmt.Println(failed, count, count-failed)
+}

4/4.go

@@ -0,0 +1,35 @@
+package main
+
+import "os"
+import "fmt"
+import "strings"
+import "bufio"
+import "sort"
+
+// cat input | go run 4.go
+
+func main() {
+
+	failed := 0
+	count := 0
+
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		count++
+		s := strings.Split(scanner.Text(), " ")
+		fmt.Println(s)
+
+		sort.Strings(s)
+		for i := 1; i < len(s); i++ {
+			fmt.Println(i, s[i])
+			if s[i] == s[i-1] {
+				failed++
+				fmt.Println("Failed!")
+				break
+			}
+		}
+
+		fmt.Println("---")
+	}
+	fmt.Println(failed, count, count-failed)
+}

5/5.go

@@ -0,0 +1,41 @@
+package main
+
+import "fmt"
+import "bufio"
+import "os"
+import "strconv"
+
+// cat input | go run 5.go
+
+func main() {
+
+	var instructions []int
+	i := 0
+	count := 0
+
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		i, _ := strconv.Atoi(scanner.Text())
+		instructions = append(instructions, i)
+	}
+
+	for {
+
+		if i >= len(instructions) {
+			fmt.Println(count)
+			os.Exit(0)
+		}
+
+		count++
+		current := instructions[i]
+
+		if instructions[i] < 3 {
+			instructions[i]++ // Just this one for the first solution
+		} else {
+			instructions[i]--
+		}
+		i += current
+
+	}
+
+}

6/6.go

@@ -0,0 +1,62 @@
+package main
+
+import "os"
+import "fmt"
+import "strconv"
+
+// go run 6.go N N N N
+
+func main() {
+
+	var banks []int
+	seen := make(map[string]int)
+
+	s := os.Args[1:]
+	for _, element := range s {
+		i, _ := strconv.Atoi(element)
+		banks = append(banks, i)
+	}
+
+	fmt.Println(banks)
+
+	count := 0
+	first := 0
+	for {
+		count++
+
+		// find largest (lowest indexed wins)
+		largest := 0
+		largestSize := -1
+		for pos, size := range banks {
+			if largestSize < size {
+				largestSize = size
+				largest = pos
+			}
+		}
+
+		fmt.Println(largest, largestSize)
+
+		// redistribute
+		banks[largest] = 0
+		for i := 0; i < largestSize; i++ {
+			largest = (largest + 1) % len(banks)
+			banks[largest]++
+		}
+
+		// laziness..
+		keep := fmt.Sprint(banks)
+
+		fmt.Println(count, keep)
+
+		if seen[keep] == 1 && first == 0 {
+			first = count
+		}
+		if seen[keep] == 2 {
+			fmt.Println("total:", count, "first:", first, "second:", (count - first))
+			os.Exit(0)
+		}
+
+		seen[keep]++
+
+	}
+}