[Leetcode] 200 Number of Islands (DFS)

[Leetcode] 200 Number of Islands (DFS)

A very basic deep-priority DFS search question. When we traverse the array and find a position of '1', we use dfs to change all the 1 around it to 0, and then recursively continue, in this way, the '1' of all connected parts is an island, sum ++, and then sum is returned. Similar questions include hdu 1016 and hdu 1241.

 

Int dir [4] [2] = {-}, {0,-1}; class Solution {public: void dfs (int I, int j, vector <vector

 
  
> & Grid) {for (int k = 0; k <4; k ++) {int x = I + dir [k] [0]; int y = j + dir [k] [1]; if (x> = 0 & x

  
   
= 0 & y

   
    
> & Grid) {int sum = 0; for (int I = 0; I