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