diff --git a/problems/kamacoder/0104.建造最大岛屿.md b/problems/kamacoder/0104.建造最大岛屿.md index 7d67b7fc..d1f27e6d 100644 --- a/problems/kamacoder/0104.建造最大岛屿.md +++ b/problems/kamacoder/0104.建造最大岛屿.md @@ -372,6 +372,123 @@ public class Main { ### Javascript +```javascript +const r1 = require('readline').createInterface({ input: process.stdin }); +// 创建readline接口 +let iter = r1[Symbol.asyncIterator](); +// 创建异步迭代器 +const readline = async () => (await iter.next()).value; + +let graph // 地图 +let N, M // 地图大小 +let visited // 访问过的节点, 标记岛屿 +const dir = [[0, 1], [1, 0], [0, -1], [-1, 0]] //方向 + +let count = 0 // 统计岛屿面积 +let areaMap = new Map() // 存储岛屿面积 + + +// 读取输入,初始化地图 +const initGraph = async () => { + let line = await readline(); + [N, M] = line.split(' ').map(Number); + graph = new Array(N).fill(0).map(() => new Array(M).fill(0)) + visited = new Array(N).fill(0).map(() => new Array(M).fill(0)) + + for (let i = 0; i < N; i++) { + line = await readline() + line = line.split(' ').map(Number) + for (let j = 0; j < M; j++) { + graph[i][j] = line[j] + } + } +} + +/** + * @description: 从(x,y)开始深度优先遍历地图 + * @param {*} graph 地图 + * @param {*} visited 可访问节点 + * @param {*} x 开始搜索节点的下标 + * @param {*} y 开始搜索节点的下标 + * @param {*} mark 当前岛屿的标记 + * @return {*} + */ +const dfs = (graph, visited, x, y, mark) => { + if (visited[x][y] != 0) return + visited[x][y] = mark + count++ + + for (let i = 0; i < 4; i++) { + let nextx = x + dir[i][0] + let nexty = y + dir[i][1] + if (nextx < 0 || nextx >= N || nexty < 0 || nexty >= M) continue //越界, 跳过 + + // 已访问过, 或者是海洋, 跳过 + if (visited[nextx][nexty] != 0 || graph[nextx][nexty] == 0) continue + + dfs(graph, visited, nextx, nexty, mark) + } +} + +(async function () { + + // 读取输入,初始化地图 + await initGraph() + + let isAllLand = true //标记整个地图都是陆地 + + let mark = 2 // 标记岛屿 + for (let i = 0; i < N; i++) { + for (let j = 0; j < M; j++) { + if (graph[i][j] == 0 && isAllLand) isAllLand = false + if (graph[i][j] === 1 && visited[i][j] === 0) { + count = 0 + dfs(graph, visited, i, j, mark) + areaMap.set(mark, count) + mark++ + } + } + } + + // 如果全是陆地, 直接返回面积 + if (isAllLand) { + console.log(N * M); + return + } + + let result = 0 // 记录最后结果 + let visitedIsland = new Map() //标记访问过的岛屿, 因为海洋四周可能是同一个岛屿, 需要标记避免重复统计面积 + for (let i = 0; i < N; i++) { + for (let j = 0; j < M; j++) { + if (visited[i][j] === 0) { + count = 1 // 记录连接之后的岛屿数量 + visitedIsland.clear() // 每次使用时,清空 + + // 计算海洋周围岛屿面积 + for (let m = 0; m < 4; m++) { + const nextx = i + dir[m][0] + const nexty = j + dir[m][1] + if (nextx < 0 || nextx >= N || nexty < 0 || nexty >= M) continue //越界, 跳过 + + const island = visited[nextx][nexty] + if (island == 0 || visitedIsland.get(island)) continue// 四周是海洋或者访问过的陆地 跳过 + + // 标记为访问, 计算面积 + visitedIsland.set(island, true) + count += areaMap.get(visited[nextx][nexty]) + } + + result = Math.max(result, count) + } + } + } + + console.log(result); +})() +``` + + + ### TypeScript ### PhP