add day 2 part 2

day2/test_reports_with_dampener.go

@@ -0,0 +1,86 @@
+package main
+
+import (
+    "fmt"
+    "os"
+    "strings"
+    "strconv"
+    "github.com/thoas/go-funk"
+)
+
+
+func check(e error) {
+    if e != nil { panic(e) }
+}
+
+func abs(n int) int {
+    if n < 0 { return -n }
+    return n
+}
+
+func pop(arr []int, idx int) []int {
+    out := make([]int, len(arr) - 1)
+
+    for i, elem := range arr {
+        if i == idx {
+            continue
+        } else if i > idx {
+            out[i - 1] = elem
+        } else {
+            out[i] = elem
+        }
+    }
+
+    return out
+}
+
+func change(s []int) []int {
+    out := make([]int, len(s) - 1)
+    for i := range out {
+        out[i] = s[i + 1] - s[i]
+    }
+    return out
+}
+
+func validate_change(change []int) bool {
+    all_neg      := len( funk.Filter(change, func(x int) bool { return x >= 0     }).([]int) ) == 0
+    all_pos      := len( funk.Filter(change, func(x int) bool { return x <= 0     }).([]int) ) == 0
+    all_abs_lt_4 := len( funk.Filter(change, func(x int) bool { return abs(x) > 3 }).([]int) ) == 0
+
+    return ( all_neg || all_pos ) && all_abs_lt_4
+}
+
+func main() {
+    // read in file as lines
+    dat, err := os.ReadFile("data.txt")
+    check(err)
+    
+    valid := 0
+    lines := strings.Split(string(dat), "\n")
+    
+    // for every non empty line
+    for _, line := range lines {
+        if line == "" { continue }
+        
+        // get numbers as array
+        str_levels := strings.Split(line, " ")
+        
+        // convert to integer
+        levels := make([]int, len(str_levels))
+        for j := range str_levels {
+            levels[j], err = strconv.Atoi(str_levels[j])
+            check(err)
+        }
+        
+        // check for valid series
+        for i := range levels {
+            slice := pop(levels, i)
+            if validate_change(change(slice)) {
+                valid++
+                break
+            }
+        }
+    }
+
+    fmt.Println(valid)
+}