tom-winckels-I7oLRdM9YIw-unsplash.jpg

代码(抄的评论区一位大神的，改成了JS，这道题让我对BFS有了新的认知)

  1. /**
  2.  * @param {character[][]} grid
  3.  * @return {number}
  4.  */
  5. var numIslands = function (grid) {
  6.   if (grid === null || grid.length === 0) {
  7.     return 0;
  8.   }
  9.   let count = 0;
  10.   for (let i = 0; i < grid.length; i++) {
  11.     for (let j = 0; j < grid[0].length; j++) {
  12.       if (grid[i][j] === "1") {
  13.         count++;
  14.         dfs(grid, i, j);
  15.       }
  16.     }
  17.   }
  18.   return count;
  19. };
  21. const dfs = (grid, i, j) => {
  22.   if (
  23.     i < 0 ||
  24.     i >= grid.length ||
  25.     j < 0 ||
  26.     j >= grid[0].length ||
  27.     grid[i][j] === "0"
  28.   ) {
  29.     return;
  30.   }
  31.   grid[i][j] = "0";
  32.   dfs(grid, i - 1, j);
  33.   dfs(grid, i + 1, j);
  34.   dfs(grid, i, j - 1);
  35.   dfs(grid, i, j + 1);
  36. };