Submission #21871280

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Source Code Expand

#include <bits/stdc++.h>

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define sf scanf
#define pf printf
#define pb push_back
#define mp make_pair
#define PI ( acos(-1.0) )
#define IN freopen("0 (1)","r",stdin)
#define OUT freopen("output.txt","w",stdout)
#define FOR(i,a,b) for(i=a ; i<=b ; i++)
#define DBG pf("Hi\n")
#define i64 long long int
#define eps (1e-9)
#define xx first
#define yy second
#define ln 17
#define sq(x) ((x)*(x))
#define fastio  ios_base::sync_with_stdio(false); cin.tie(NULL)



using namespace __gnu_pbds;
using namespace std ;

typedef tree< i64, null_type, less<i64>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
typedef pair<i64, i64> pii;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

#define maxn 400005
#define log 20
#define mod 3
#define INF 1500000000000000000LL
#define off 500005

vector<int> g[maxn] ;
int par[maxn] , dis[maxn] ;

pair<int,int> bfs(int src,int n)
{
    for(int i=1 ; i<=n ; i++) dis[i] = -1 , par[i] = 0 ;
    dis[src] = 0 ;
    queue<int> q ;
    q.push(src) ;

    while(!q.empty()){
        int u = q.front() ;
        q.pop() ;
        for(int v:g[u]){
            if( dis[v]==-1 ){
                q.push(v) ;
                dis[v] = dis[u] + 1 ;
                par[v] = u ;
            }
        }
    }
    pair<int,int> ans = mp(-1,-1) ;
    for(int i=1 ; i<=n ; i++) ans = max( ans , mp(dis[i],i) ) ;
    return ans ;
}

int ans[maxn] ;

void dfs(int u, int p, int &cur )
{
 //   printf("%d %d %d\n",u,p,cur) ;

    cur++ ;
    ans[u] = cur ;

    for(int v:g[u]){
        if(v==p || v==par[u]) continue ;
        dfs(v,u,cur) ;
    }

    if( par[u]!=0 && par[u]!=p ) dfs(par[u],u,cur) ;

    cur++ ;
    return ;
}

int main()
{
    int n ;
    scanf("%d",&n) ;

    for(int i=1 ; i<n ; i++){
        int u , v ;
        scanf("%d %d",&u,&v) ;
        g[u].pb(v) ; g[v].pb(u) ;
    }

    int u = bfs(1,n).yy ;
    u = bfs(u,n).yy ;

//    printf("-- %d\n",u) ;
//    for(int i=1 ; i<=n ; i++) printf("%d ",par[i]) ;
//    printf("\n") ;

    bool fl = 0 ;

    int cur = 0 ;
    dfs(u,0,cur) ;

    for(int i=1 ; i<=n ; i++) printf("%d ",ans[i]) ;
    printf("\n") ;

    return 0 ;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:102:10: warning: unused variable ‘fl’ [-Wunused-variable]
  102 |     bool fl = 0 ;
      |          ^~
./Main.cpp:87:10: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   87 |     scanf("%d",&n) ;
      |     ~~~~~^~~~~~~~~
./Main.cpp:91:14: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   91 |         scanf("%d %d",&u,&v) ;
      |         ~~~~~^~~~~~~~~~~~~~~

Judge Result