SearchIsland.go

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var Dir [][]int

var M, N int
var MZ [][]int
var ANS int

func init() {
	Dir = [][]int{
		{0, 1},  // U
		{1, 0},  // R
		{0, -1}, // D
		{-1, 0}, // L
	}
}

func scan(ch chan int) {
	defer close(ch)
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	for sc.Scan() {
		txt := sc.Text()
		x, err := strconv.Atoi(txt)
		if err != nil {
			panic(err.Error())
		}
		ch <- x
	}
	if err := sc.Err(); err != nil {
		panic("scann error!")
	}
}

func read() {
	ch := make(chan int)
	go scan(ch)

	M = <-ch
	N = <-ch

	MZ = make([][]int, N+1)
	for i := 0; i < N; i++ {
		MZ[i] = make([]int, M+1)
		for j := 0; j < M; j++ {
			MZ[i][j] = <-ch
		}
	}
}

func dfs(y, x int) {
	MZ[y][x] = 0
	for _, d := range Dir {
		dx, dy := x+d[0], y+d[1]
		if dx < 0 || dx >= M || dy < 0 || dy >= N {
			continue
		}
		if MZ[dy][dx] == 0 {
			continue
		}
		dfs(dy, dx)
	}
}

func p() {
	for i := 0; i < N; i++ {
		fmt.Println(MZ[i])
	}
	println()
}

func solve() int {
	for i := 0; i < N; i++ {
		for j := 0; j < M; j++ {
			if MZ[i][j] == 1 {
				// p()
				dfs(i, j)
				ANS++
			}
		}
	}
	return 0
}

func answer() {
	fmt.Println(ANS)
}

func main() {
	read()
	solve()
	answer()
}