Leetcode 1971. 寻找图中是否存在路径 DFS/BFS

原题链接：Leetcode 1971. 寻找图中是否存在路径

DFS

class Solution {
    
    
public:
    vector<vector<int>> adj;
    vector<int> visit;
    bool flag=false;
    void dfs(int now,int destination)
    {
    
    
        if(now==destination) flag=true;
        visit[now]=1;
        for(auto x:adj[now])
        {
    
    
            if(!visit[x]) dfs(x,destination);
        }
    }
    bool validPath(int n, vector<vector<int>>& edges, int source, int destination) {
    
    
        adj.resize(n);
        visit.resize(n);
        for(auto x:edges)
        {
    
    
            int a=x[0],b=x[1];
            adj[a].push_back(b);
            adj[b].push_back(a);
        }
        dfs(source,destination);
        return flag;
    }
};

BFS

class Solution {
    
    
public:
    vector<vector<int>> adj;
    vector<int> visit;
    bool validPath(int n, vector<vector<int>>& edges, int source, int destination) {
    
    
        if(source==destination) return true;
        adj.resize(n);
        visit.resize(n);
        for(auto x:edges)
        {
    
    
            int a=x[0],b=x[1];
            adj[a].push_back(b);
            adj[b].push_back(a);
        }
        queue<int> q; q.push(source);
        visit[source]=1;
        while(!q.empty())
        {
    
    
            int now=q.front(); q.pop();
            for(auto x:adj[now])
            {
    
    
               if(!visit[x]) 
               {
    
    
                    if(x==destination)  return true;
                    visit[x]=1;
                    q.push(x);
               }
           }
        }
        return false;
    }
};