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top-100-liked/51/leetcode_test.go

@@ -0,0 +1,62 @@
+package top100liked
+
+import (
+	"fmt"
+	"testing"
+)
+
+// https://leetcode.cn/problems/number-of-islands/?envType=study-plan-v2&envId=top-100-liked
+
+func numIslands(grid [][]byte) int {
+	m := len(grid)
+	n := len(grid[0])
+	visited := make([][]bool, m)
+	for i := range m {
+		visited[i] = make([]bool, n)
+	}
+	res := 0
+	type point struct {
+		Row    int
+		Column int
+	}
+	queue := []point{}
+	for i := range m {
+		for j := range n {
+			if !visited[i][j] && grid[i][j] == '1' {
+				queue = append(queue, point{i, j})
+				visited[i][j] = true
+				res++
+			}
+			for len(queue) > 0 {
+				cur := queue[0]
+				queue = queue[1:]
+				// 左侧
+				if cur.Column > 0 && !visited[cur.Row][cur.Column-1] && grid[cur.Row][cur.Column-1] == '1' {
+					queue = append(queue, point{cur.Row, cur.Column - 1})
+					visited[cur.Row][cur.Column-1] = true
+				}
+				// 右侧
+				if cur.Column+1 < n && !visited[cur.Row][cur.Column+1] && grid[cur.Row][cur.Column+1] == '1' {
+					queue = append(queue, point{cur.Row, cur.Column + 1})
+					visited[cur.Row][cur.Column+1] = true
+				}
+				// 上侧
+				if cur.Row > 0 && !visited[cur.Row-1][cur.Column] && grid[cur.Row-1][cur.Column] == '1' {
+					queue = append(queue, point{cur.Row - 1, cur.Column})
+					visited[cur.Row-1][cur.Column] = true
+				}
+				// 下侧
+				if cur.Row+1 < m && !visited[cur.Row+1][cur.Column] && grid[cur.Row+1][cur.Column] == '1' {
+					queue = append(queue, point{cur.Row + 1, cur.Column})
+					visited[cur.Row+1][cur.Column] = true
+				}
+			}
+		}
+	}
+	return res
+}
+
+func Test(t *testing.T) {
+	input := [][]byte{{'1', '1', '1'}, {'0', '1', '0'}, {'1', '1', '1'}}
+	fmt.Println(numIslands(input))
+}