diff --git a/problems/0827.最大人工岛.md b/problems/0827.最大人工岛.md index 3f32dd7a..7930c7a1 100644 --- a/problems/0827.最大人工岛.md +++ b/problems/0827.最大人工岛.md @@ -348,6 +348,99 @@ class Solution: ``` + +### Go + +```go +func largestIsland(grid [][]int) int { + dir := [][]int{{0, 1}, {1, 0}, {-1, 0}, {0, -1}} + n := len(grid) + m := len(grid[0]) + area := 0 + visited := make([][]bool, n) + for i := 0; i < n; i++ { + visited[i] = make([]bool, m) + } + gridNum := make(map[int]int, 0) // 记录每一个岛屿的面积 + mark := 2 // 记录每个岛屿的编号 + isAllGrid := true + res := 0 // 标记是否整个地图都是陆地 + + var dfs func(grid [][]int, visited [][]bool, x, y, mark int) + dfs = func(grid [][]int, visited [][]bool, x, y, mark int) { + // 终止条件:访问过的节点 或者 遇到海水 + if visited[x][y] || grid[x][y] == 0 { + return + } + visited[x][y] = true // 标记访问过 + grid[x][y] = mark // 给陆地标记新标签 + area++ + for i := 0; i < 4; i++ { + nextX := x + dir[i][0] + nextY := y + dir[i][1] + if nextX < 0 || nextX >= len(grid) || nextY < 0 || nextY >= len(grid[0]) { + continue + } + dfs(grid, visited, nextX, nextY, mark) + } + } + + for i := 0; i < n; i++ { + for j := 0; j < m; j++ { + if grid[i][j] == 0 { + isAllGrid = false + } + if !visited[i][j] && grid[i][j] == 1 { + area = 0 + dfs(grid, visited, i, j, mark) // 将与其链接的陆地都标记上 true + gridNum[mark] = area // 记录每一个岛屿的面积 + mark++ // 更新下一个岛屿编号 + } + } + } + if isAllGrid { + return n * m + } + // 根据添加陆地的位置,计算周边岛屿面积之和 + visitedGrid := make(map[int]struct{}) // 标记访问过的岛屿 + for i := 0; i < n; i++ { + for j := 0; j < m; j++ { + count := 1 // 记录连接之后的岛屿数量 + visitedGrid = make(map[int]struct{}) // 每次使用时,清空 + if grid[i][j] == 0 { + for k := 0; k < 4; k++ { + // 计算相邻坐标 + nearI := i + dir[k][0] + nearJ := j + dir[k][1] + if nearI < 0 || nearI >= len(grid) || nearJ < 0 || nearJ >= len(grid[0]) { + continue + } + // 添加过的岛屿不要重复添加 + if _, ok := visitedGrid[grid[nearI][nearJ]]; ok { + continue + } + // 把相邻四面的岛屿数量加起来 + count += gridNum[grid[nearI][nearJ]] + // 标记该岛屿已经添加过 + visitedGrid[grid[nearI][nearJ]] = struct{}{} + } + } + res = max827(res, count) + } + } + return res +} + +func max827(x, y int) int { + if x > y { + return x + } + return y +} + +``` + + ### JavaScript ```JavaScript @@ -411,8 +504,6 @@ return res; ``` - -