增加建造最大岛屿代码go语言版本

problems/kamacoder/0104.建造最大岛屿.md

@@ -528,6 +528,104 @@ if __name__ == "__main__":
 
 ### Go
 
+```go
+package main
+
+import "fmt"
+
+func main() {
+    var m, n int
+    fmt.Scan(&m, &n)
+
+    grid := make([][]int, m)
+    for i := range grid {
+        grid[i] = make([]int, n)
+        for j := range grid[i] {
+            fmt.Scan(&grid[i][j])
+        }
+    }
+
+    sum := buildMaxIsland(grid)
+    fmt.Println(sum)
+}
+
+
+func buildMaxIsland(grid [][]int) int {
+	result := 0
+	if grid == nil || len(grid) == 0 {
+		return result
+	}
+	hashMap := make(map[int]int)
+	islandArea := 0
+	gridMark := 2
+	for i := 0; i < len(grid); i++ {
+		for j := 0; j < len(grid[0]); j++ {
+			if grid[i][j] == 1 {
+				islandArea = 0
+				visitGrid4(grid, i, j, &islandArea, gridMark)
+				hashMap[gridMark] = islandArea
+				if islandArea > result {
+					result = islandArea
+				}
+				gridMark++
+			}
+		}
+	}
+
+	for i := 0; i < len(grid); i++ {
+		for j := 0; j < len(grid[0]); j++ {
+			if grid[i][j] == 0 {
+				sum := findNearByIsland(grid, i, j, hashMap)
+				if sum > result {
+					result = sum
+				}
+			}
+		}
+	}
+
+	return result
+}
+
+func visitGrid4(grid [][]int, x int, y int, preValue *int, gridMark int) {
+	if x < 0 || y < 0 || x >= len(grid) || y >= len(grid[0]) {
+		return
+	}
+	//可以省略掉visited的原因是因为grid的每个位置如果被遍历过就会被标记为gridMark，能识别出来是不是被遍历过
+	if grid[x][y] != 1 {
+		return
+	}
+	// visited[x][y] = true
+	grid[x][y] = gridMark
+	*preValue++
+	visitGrid4(grid, x+1, y, preValue, gridMark)
+	visitGrid4(grid, x-1, y, preValue, gridMark)
+	visitGrid4(grid, x, y+1, preValue, gridMark)
+	visitGrid4(grid, x, y-1, preValue, gridMark)
+}
+
+func findNearByIsland(grid [][]int, x, y int, hashMap map[int]int) int {
+	markSet := make(map[int]bool)
+	sum := 1
+	coordinate := [][]int{{x + 1, y}, {x - 1, y}, {x, y + 1}, {x, y - 1}}
+	for _, arr := range coordinate {
+		if arr[0] < 0 || arr[1] < 0 || arr[0] >= len(grid) || arr[1] >= len(grid[0]) {
+			continue
+		}
+		if grid[arr[0]][arr[1]] == 0 {
+			continue
+		}
+		gridMark := grid[arr[0]][arr[1]]
+		if !markSet[gridMark] {
+			markSet[gridMark] = true
+			sum += hashMap[gridMark]
+		}
+	}
+	return sum
+}
+```
+
+
+
 ### Rust
 
 ### JavaScript