Submission #279680

#	Time	Username	Problem	Language	Result	Execution time	Memory
279680		infinite_iq	Dynamic Diameter (CEOI19_diameter)	C++14	18 / 100	483 ms	11768 KiB

diameter

    #define fast ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0)
    #include <bits/stdc++.h>
    using namespace std;
    #define sqr 340
    #define mp make_pair
    #define mid (l+r)/2
    #define le node * 2 
    #define ri node * 2 + 1 
    #define pb push_back
    #define ppb pop_back
    #define fi first
    #define se second
    #define lb lower_bound
    #define ub upper_bound
    #define ins insert
    #define era erase
    #define C continue
    #define mem(dp,i) memset(dp,i,sizeof(dp))
    #define mset multiset
    #define all(x) x.begin(), x.end()
    #define gc getchar_unlocked
    typedef long long ll;
    typedef short int si;
    typedef long double ld;
    typedef pair<int,int> pi;
    typedef pair<ll,ll> pll;
    typedef vector<int> vi;
    typedef vector<ll> vll;
    typedef vector<pi> vpi;
    typedef vector<pll> vpll;
    typedef pair<double,ll>pdi;
    const ll inf=1e18;
    const ll Mod=1e9+7;
    const ld Pi=acos(-1) ;
    int n , q , MX ;
    vpi v [100009] ;
    pi edges [100009] ;
    //
    void input () {
            cin >> n >> q >> MX ;
            for ( int i = 0 ; i < n - 1 ; i ++ ) {
                    int a , b , c ;
                    scanf ("%d%d%d", &a , &b , &c ) ;
                    a -- , b -- ;
                    edges [i] = { a , b } ;
                    v [a] .pb ( { b , c } ) ;
                    v [b] .pb ( { a , c } ) ;
            }
    }
    // Sub1_2
    pi Far ;
    int Sub1_2 () {
            return ( n <= 5009 && q <= 5009 ) ;
    }
    void Dfs1 ( int node , int p , int Crnt ) {
            Far = max ( Far , { Crnt , node } ) ;
            for ( auto u : v [node] ) {
                    if ( u .fi == p ) C ;
                    Dfs1 ( u .fi , node , Crnt + u .se ) ;
            }
    }
    int BruteForce () {
            Far = { 0 , 0 } ;
            Dfs1 ( 0 , 0 , 0 ) ;
            Dfs1 ( Far .se , Far .se , 0 ) ;
            return Far .fi ;
    }
    void Sol1_2 () {
            int Last = 0 ;
            while ( q -- ) {
                    int id , cost ;
                    cin >> id >> cost ;
                    id   = ( id   + Last ) % ( n - 1 ) ;
                    cost = ( cost + Last ) % ( MX    ) ;
                    int a = edges [id] .fi , b = edges [id] .se ;
                    for ( auto &u : v [a] ) {
                            if ( u .fi == b ) {
                                    u .se = cost ;
                                    break ;
                            }
                    }
                    for ( auto &u : v [b] ) {
                            if ( u .fi == a ) {
                                    u .se = cost ;
                                    break ;
                            }
                    }
                    Last = BruteForce () ;
                    cout << Last << endl ;
            }
    }
    // Sub4 
    int Dp [100009] , Mx [100009] , P [100009] ;
    int Sub4 () {
            for ( int i = 0 ; i < n - 1 ; i ++ ) {
                    int a = edges [i] .fi , b = edges [i] .se ;
                    if ( a > b ) {
                            swap ( edges [i] .fi , edges [i] .se ) ;
                    }
                    a ++ , b ++ ;
                    if ( a * 2 != b && a * 2 + 1 != b ) return 0 ;
            }
            return 1 ;
    }
    void Fill ( int node , int p ) {
            P [node] = p ;
            for ( auto u : v [node] ) {
                    if ( u .fi == p ) C ;
                    Fill ( u .fi , node ) ;
                    Dp [node] = max ( Dp [node] , Dp [u.fi] ) ;
                    Dp [node] = max ( Dp [node] , Mx [u.fi] + u .se + Mx [node] ) ;
                    Mx [node] = max ( Mx [node] , Mx [u.fi] + u .se ) ;
            }
            Dp [node] = max ( Dp [node] , Mx [node] ) ;
    }
    void Up ( int node ) {
            Dp [node] = 0 , Mx [node] = 0 ;
            for ( auto u : v [node] ) {
                    if ( u .fi == P [node] ) C ;
                    Dp [node] = max ( Dp [node] , Dp [u.fi] ) ;
                    Dp [node] = max ( Dp [node] , Mx [u.fi] + u .se + Mx [node] ) ;
                    Mx [node] = max ( Mx [node] , Mx [u.fi] + u .se ) ;
            }
            if ( P [node] != node )
                    Up ( P  [node] ) ;
    }
    void Sol4 () {
            Fill ( 0 , 0 ) ;
            int Last = 0 ;
            while ( q -- ) {
                    int id , cost ;
                    cin >> id >> cost ;
                    id   = ( id   + Last ) % ( n - 1 ) ;
                    cost = ( cost + Last ) % ( MX    ) ;
                    int a = edges [id] .fi , b = edges [id] .se ;
                    for ( auto &u : v [a] ) {
                            if ( u .fi == b ) {
                                    u .se = cost ;
                                    break ;
                            }
                    }
                    for ( auto &u : v [b] ) {
                            if ( u .fi == a ) {
                                    u .se = cost ;
                                    break ;
                            }
                    }
                    Up ( a ) ;
                    Last =  Dp [0] ;
                    cout << Dp [0] << endl ;
            }
    }
    int main () {
            input () ;
        //    if ( Sub1_2 () ) Sol1_2 () ;
            if ( Sub4   () ) Sol4   () ;
    //      if ( Sub3_5 () ) Sol3_5 () ; 
    }

Compilation message (stderr)

diameter.cpp: In function 'void input()':
diameter.cpp:43:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   43 |                     scanf ("%d%d%d", &a , &b , &c ) ;
      |                     ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 11
• Subtask 2: 0 / 13
• Subtask 3: 0 / 7
• Subtask 4: 18 / 18
• Subtask 5: 0 / 24
• Subtask 6: 0 / 27