CSAcademy Check DFS

/*
    Verdict: Accepted

    ** One of Interesting problem I have ever seen by DFS **


*/

#include<bits/stdc++.h>

using namespace std;

#define fast ios_base::sync_with_stdio(0)
#define bfast cin.tie(0)
#define outs(x) cout << x << " "
#define outn(x) cout << x << "\n"
#define sf scanf
#define pf printf
#define pfn(x , k) printf(k , x)
#define nl puts("")
#define psb push_back
#define mset(c,v) memset(c , v , sizeof c)
#define loop0(n) for(int i=0; i<n; i++)
#define loop1(n) for(int i=1; i<=n; i++)
#define mpair(x , y) make_pair(x , y)
#define all(x) x.begin(), x.end()
#define pi acos(-1.0)
#define psb push_back
#define clr clear()

typedef unsigned long long ull;
typedef long long LL;
typedef vector<int>vii;
typedef vector<LL>vll;
typedef vector<string>vs;
typedef map<int, int>mpii;
typedef map<string, int>mpsi;
typedef map<char, int>mpci;
typedef map<LL, LL>mpll;

const int mod = 1000007;
const int high = 1e5+3;

int visited[high] , order[high] , p[high];

vii adj[high] , dfsOrder;

void cln()
{
    for(int i=0; i<high; i++)
    {
        adj[i].clr;
        visited[i] = 0;
        order[i] = 0;
    }

    dfsOrder.clr;
}

bool cmp(int a , int b)
{
    return order[a] < order[b];
}

void DFS(int u)
{
    visited[u] = 1;

    dfsOrder.psb(u);

    int len = adj[u].size() , v=0;

    for(int i=0; i<len; i++)
    {
        v = adj[u][i];

        if(!visited[v])
        {
            DFS(v);
        }
    }
}

int main()
{
    fast;
    int i , j , u , v , N , M , x;
    while(cin >> N >> M)
    {
        cln();

        for(i=1; i<=N; i++)
        {
            cin >> x;

            order[x] = i;
            p[i] = x;
        }

        for(i=0; i<M; i++)
        {
            cin >> u >> v;

            adj[u].psb(v);
            adj[v].psb(u);
        }

        for(i=1; i<=N; i++)
        {
            int len = adj[i].size();

            for(j=0; j<len; j++)
            {
                sort(adj[i].begin(), adj[i].end() , cmp);
            }
        }


        DFS(1); //outn("\n");

        bool fl=true;

        for(i=1; i<=N; i++)
        {
            if(p[i] != dfsOrder[i-1])
            {
                fl=false;
                break;
            }
        }

        if(fl) outn(1);
        else outn(0);

//        for(i=1; i<=N; i++)
//        {
//            cout << "for node " << i << ": ";
//
//            for(j=0; j<adj[i].size(); j++)
//            {
//                cout << adj[i][j] << "; ";
//            }
//
//            cout << '\n';
//        }
    }

    return 0;
}