LeetCode75-547-Number-of-Province

🧠 Summary of Thoughts

Review Foundation 1 (CSE 2321), Adjacency Matrix is a method to interpret graph.

For example: isConnected[i][j]. If 1, then i and j has edge to connect. Else (0), no edge between i and j.

✅ Code（Java）

class Solution {
    public int findCircleNum(int[][] isConnected) {
        int size = isConnected.length;
        int ans = 0;
        boolean[] visited = new boolean[size];
        for (int i = 0; i < size;i++) {
            if (!visited[i]) {
                dfs(isConnected, visited, i);
                ans++;
            }
        }
        return ans;
    }
    private static void dfs(int[][] isConnected, boolean[] visited, int i) {
        visited[i] = true;
        for (int j = 0; j < isConnected.length; j++) {
            if (isConnected[i][j] == 1 && !visited[j]) {
                dfs(isConnected, visited, j);
            }
        }
    }
}