LeetCode 1345. Jump Game IV(BFS)

struct Node
{
    int pos;
    int num;
    Node(){}
    Node(int pos,int num)
    {
        this->pos = pos;
        this->num = num;
    }
};
class Solution {
public:
    map<int,vector<int>> m;
    int vis[50005];
    int minJumps(vector<int>& arr) {
        
        for(int i=1;i<arr.size();i++)
        {
            vis[i]=99999999;
            m[arr[i]].push_back(i);
        }
        
        queue<Node> q;
        int ans=0;
        q.push(Node(0,0));
        vis[0]=0;
        
        while(!q.empty())
        {
            Node term = q.front();
            q.pop();
            
            if(term.pos==arr.size()-1)
                ans = term.num;
            //往后走一步
            if(term.pos>0)
            {
                if(vis[term.pos-1]>term.num+1)
                {
                    q.push(Node(term.pos-1,term.num+1));
                    vis[term.pos-1]=term.num+1;
                }
            }
            
            //往前走一步
            if(vis[term.pos+1]>term.num+1)
            {
                q.push(Node(term.pos+1,term.num+1));
                vis[term.pos+1]=term.num+1;
            }
            
            //相同数值的位置
            for(int i=0;i<m[arr[term.pos]].size();i++)
            {
                if(m[arr[term.pos]][i]==term.pos)
                    continue;
               
                if(vis[m[arr[term.pos]][i]]>=term.num+1)
                {
                    q.push(Node(m[arr[term.pos]][i],term.num+1));
                    vis[m[arr[term.pos]][i]] = term.num+1;
                }
                else
                    break;//防止之后再次循环，超时。
            }
            
        }
        return ans;
        
    }

};