count_areas_in_map.go

package main

import "fmt"

func main() {
	slice1 := [][]int{
		[]int{1, 1, 1, 6, 6, 6, 6, 5},
		[]int{1, 1, 1, 6, 6, 4, 6, 5},
		[]int{6, 6, 6, 6, 3, 4, 6, 5},
		[]int{6, 2, 2, 6, 3, 3, 5, 5},
	}

	slice2 := [][]int{
		[]int{1, 1, 1, 6, 6, 6, 6, 5},
		[]int{1, 2, 1, 6, 6, 4, 6, 5},
		[]int{6, 6, 6, 6, 3, 4, 6, 5},
		[]int{7, 2, 2, 6, 3, 3, 5, 5},
		[]int{7, 8, 8, 6, 3, 3, 1, 5},
		[]int{7, 8, 9, 6, 3, 3, 1, 5},
	}
	fmt.Println("count map 1")
	for i := range slice1 {
		fmt.Println(slice1[i])
	}
	count := countAreas(slice1)
	fmt.Println("areas:", count)

	fmt.Println("count map 2")
	for i := range slice2 {
		fmt.Println(slice2[i])
	}
	count = countAreas(slice2)
	fmt.Println("areas:", count)
}

func countAreas(Map [][]int) int {
	areas := 0
	Y := len(Map)
	X := len(Map[0])

	// fill a check map (same size as map) with false
	checkMap := make([][]bool, Y)
	for i := range checkMap {
		checkMap[i] = make([]bool, X)
	}

	for i := 0; i < X; i++ {
		for j := 0; j < Y; j++ {
			if !checkMap[j][i] {
				areas++
				lookAround(Map, checkMap, i, j, Map[j][i])
			}
		}
	}

	return areas
}

func lookAround(originMap [][]int, checkMap [][]bool, x int, y int, mark int) bool {
	Y := len(originMap)
	X := len(originMap[0])
	if x < 0 || x >= X || y < 0 || y >= Y || checkMap[y][x] == true {
		return false
	}

	if originMap[y][x] == mark {
		// start looking around
		checkMap[y][x] = true
		lookAround(originMap, checkMap, x-1, y, mark)
		lookAround(originMap, checkMap, x+1, y, mark)
		lookAround(originMap, checkMap, x, y-1, mark)
		lookAround(originMap, checkMap, x, y+1, mark)
		return true
	}
	return true
}

func check(e error) {
	if e != nil {
		panic(e)
	}
}