33 lines
839 B
JavaScript
33 lines
839 B
JavaScript
/**
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* @param {character[][]} grid
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* @return {number}
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*/
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export const numIslands = function (grid) {
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if (!grid[0]) return 0
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const maxN = grid.length - 1
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const maxI = grid[0].length - 1
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const overtrun = (n, i) => { // 沉没上下左右的岛屿
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if (Number(grid[n][i]) === 1) {
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grid[n][i] = 0
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if (i - 1 >= 0) overtrun(n, i - 1) // 上
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if (i + 1 <= grid[0].length - 1) overtrun(n, i + 1) // 下
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if (n - 1 >= 0) overtrun(n - 1, i) // 左
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if (n + 1 <= grid.length - 1) overtrun(n + 1, i) // 右
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}
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}
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let res = 0
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// 1. 遍历所有的点
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for (let n = 0; n <= maxN; n++) {
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for (let i = 0; i <= maxI; i++) {
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if (Number(grid[n][i]) === 1) { // 2. 如果是岛屿，就将其上下左右都为1的岛屿沉没
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res++
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overtrun(n, i)
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}
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}
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}
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return res
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}
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