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@@ -0,0 +1,86 @@
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+package main
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+
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+import (
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+ "bufio"
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+ "fmt"
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+ "log"
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+ "os"
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+)
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+
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+func readInput(file *os.File) [][]byte {
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+ scanner := bufio.NewScanner(file)
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+ var matrix [][]byte
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+
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+ for scanner.Scan() {
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+ line := scanner.Text()
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+ if line == "" {
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+ break
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+ }
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+
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+ matrix = append(matrix, []byte(line))
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+ }
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+
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+ return matrix
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+}
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+
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+func countWordOccurrences(matrix [][]byte, word string) int {
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+ rows, cols := len(matrix), len(matrix[0])
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+ count := 0
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+ found := make(map[string]bool)
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+
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+ var dfs func(i, j, wordIndex int, wordSoFar string)
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+ dfs = func(i, j, wordIndex int, wordSoFar string) {
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+ // Base case: we've matched all characters of the word
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+ if wordIndex == len(word) {
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+ if !found[wordSoFar] {
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+ found[wordSoFar] = true
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+ count++
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+ }
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+
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+ return
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+ }
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+
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+ // Check if the current position is valid
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+ if i < 0 || i >= rows || j < 0 || j >= cols || matrix[i][j] != word[wordIndex] {
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+ return
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+ }
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+
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+ wordSoFar = fmt.Sprintf("%s%d_%d%c", wordSoFar, i, j, matrix[i][j])
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+
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+ // Move to the next character in the word
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+ dfs(i+1, j, wordIndex+1, wordSoFar) // Down
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+ dfs(i-1, j, wordIndex+1, wordSoFar) // Up
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+ dfs(i, j+1, wordIndex+1, wordSoFar) // Right
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+ dfs(i, j-1, wordIndex+1, wordSoFar) // Left
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+ dfs(i+1, j+1, wordIndex+1, wordSoFar) // Diagonal down-right
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+ dfs(i-1, j-1, wordIndex+1, wordSoFar) // Diagonal up-left
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+ dfs(i+1, j-1, wordIndex+1, wordSoFar) // Diagonal down-left
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+ dfs(i-1, j+1, wordIndex+1, wordSoFar) // Diagonal up-right
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+ }
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+
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+ // Try each cell as a starting point
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+ for i := 0; i < rows; i++ {
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+ for j := 0; j < cols; j++ {
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+ if matrix[i][j] == word[0] {
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+ dfs(i, j, 0, "")
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+ }
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+ }
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+ }
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+ fmt.Println(found)
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+ return count
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+}
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+
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+func main() {
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+ if len(os.Args) < 2 {
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+ log.Fatal("You need to specify a file!")
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+ }
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+
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+ filePath := os.Args[1]
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+ file, err := os.Open(filePath)
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+ if err != nil {
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+ log.Fatalf("Failed to open %s!\n", filePath)
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+ }
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+
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+ matrix := readInput(file)
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+ fmt.Println("Part1:", countWordOccurrences(matrix, "XMAS"))
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+}
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