【HDU】5436 Transmigration tree【树链剖分+dp+rmq】

题目链接：【HDU】5436 Transmigration tree

#pragma comment(linker, "/STACK:16777216")#include <stdio.h>#include <string.h>#include <vector>#include <algorithm>using namespace std ;typedef long long LL ;#define clr( a , x ) memset ( a , x , sizeof a )const int MAXN = 50005 ;vector < int > G[MAXN] ;int dep[MAXN] ;int siz[MAXN] ;int son[MAXN] ;int pre[MAXN] ;int pos[MAXN] ;int top[MAXN] ;int tree_idx ;int maxv[MAXN][18] ;int dp[MAXN][2] ;int qp[MAXN][2] ;pair < int , int > up[MAXN] ;pair < int , int > L[MAXN] ;pair < int , int > R[MAXN] ;int w[MAXN] ;int sum[MAXN] ;int n , q ;void dfs ( int u ) {    son[u] = 0 ;    siz[u] = 1 ;    for ( int i = 0 ; i < G[u].size () ; ++ i ) {        int v = G[u][i] ;        pre[v] = u ;        dep[v] = dep[u] + 1 ;        dfs ( v ) ;        siz[u] += siz[v] ;        if ( siz[v] > siz[son[u]] ) son[u] = v ;    }}void rebuild ( int u , int top_element ) {    pos[u] = ++ tree_idx ;    top[u] = top_element ;    if ( son[u] ) rebuild ( son[u] , top_element ) ;    for ( int i = 0 ; i < G[u].size () ; ++ i ) {        int v = G[u][i] ;        if ( v != pre[u] && v != son[u] ) rebuild ( v , v ) ;    }}void dfs2 ( int u ) {    qp[u][0] = 1e9 ;    qp[u][1] = 0 ;    int leaf = 1 ;    for ( int i = 0 ; i < G[u].size () ; ++ i ) {        int v = G[u][i] ;        dp[v][0] = dp[u][0] + w[pos[v]] ;        dp[v][1] = max ( dp[u][1] , w[pos[v]] ) ;        dfs2 ( v ) ;        leaf = 0 ;        if ( qp[u][0] > qp[v][0] ) {            qp[u][0] = qp[v][0] ;            qp[u][1] = qp[v][1] ;        } else if ( qp[u][0] == qp[v][0] ) {            qp[u][1] = max ( qp[u][1] , qp[v][1] ) ;        }    }    if ( leaf ) qp[u][0] = w[pos[u]] ;    else qp[u][0] += w[pos[u]] ;    qp[u][1] = max ( qp[u][1] , w[pos[u]] ) ;}void dfs3 ( int u ) {    int n = G[u].size () ;    if ( n == 0 ) return ;    L[0] = make_pair ( -1e9 , 0 ) ;    R[n - 1] = make_pair ( -1e9 , 0 ) ;    for ( int i = 1 ; i < n ; ++ i ) {        int v = G[u][i - 1] ;        L[i] = max ( L[i - 1] , make_pair ( -qp[v][0] , qp[v][1] ) ) ;    }    for ( int i = n - 2 ; i >= 0 ; -- i ) {        int v = G[u][i + 1] ;        R[i] = max ( R[i + 1] , make_pair ( -qp[v][0] , qp[v][1] ) ) ;    }    for ( int i = 0 ; i < n ; ++ i ) {        int v = G[u][i] ;        pair < int , int > t = max ( L[i] , R[i] ) ;        up[v] = max ( up[u] , make_pair ( t.first - w[pos[u]] , max ( t.second , w[pos[u]] ) ) ) ;        up[v].first -= w[pos[v]] ;        up[v].second = max ( up[v].second , w[pos[v]] ) ;    }    for ( int i = 0 ; i < n ; ++ i ) {        int v = G[u][i] ;        dfs3 ( v ) ;    }}void init_RMQ ( int n ) {    for ( int i = 1 ; i <= n ; ++ i ) maxv[i][0] = w[i] ;    for ( int j = 1 ; ( 1 << j ) < n ; ++ j ) {        for ( int i = 1 ; i + ( 1 << j ) - 1 <= n ; ++ i ) {            maxv[i][j] = max ( maxv[i][j - 1] , maxv[i + ( 1 << ( j - 1 ) )][j - 1] ) ;        }    }}int rmq ( int L , int R , int k = 0 ) {    while ( ( 1 << ( k + 1 ) ) <= R - L + 1 ) ++ k ;    return max ( maxv[L][k] , maxv[R - ( 1 << k ) + 1][k] ) ;}pair < int , int > getval ( int x , int y ) {    int ans1 = 0 , ans2 = 0 ;    while ( top[x] != top[y] ) {        if ( dep[top[x]] < dep[top[y]] ) swap ( x , y ) ;        ans1 += sum[pos[x]] - sum[pos[top[x]] - 1] ;        ans2 = max ( ans2 , rmq ( pos[top[x]] , pos[x] ) ) ;        x = pre[top[x]] ;    }    if ( dep[x] > dep[y] ) swap ( x , y ) ;    ans1 += sum[pos[y]] - sum[pos[x] - 1] ;    ans2 = max ( ans2 , rmq ( pos[x] , pos[y] ) ) ;    return make_pair ( -ans1 , ans2 ) ;}void solve () {    int u , v ;    tree_idx = 0 ;    scanf ( "%d%d" , &n , &q ) ;    for ( int i = 1 ; i <= n ; ++ i ) {        G[i].clear () ;    }    for ( int i = 2 ; i <= n ; ++ i ) {        scanf ( "%d" , &u ) ;        G[u].push_back ( i ) ;    }    dfs ( 1 ) ;    rebuild ( 1 , 1 ) ;    for ( int i = 1 ; i <= n ; ++ i ) {        scanf ( "%d" , &w[pos[i]] ) ;    }    dp[1][0] = w[pos[1]] ;    dp[1][1] = w[pos[1]] ;    up[1] = make_pair ( -1e9 , 0 ) ;    for ( int i = 2 ; i <= n ; ++ i ) {        dp[i][0] = dp[i][1] = 0 ;    }    dfs2 ( 1 ) ;    dfs3 ( 1 ) ;    for ( int i = 1 ; i <= n ; ++ i ) {        pair < int , int > t = make_pair ( -qp[i][0] , qp[i][1] ) ;        if ( t < up[i] ) t = up[i] ;        qp[i][0] = -t.first ;        qp[i][1] = t.second ;    }    init_RMQ ( n ) ;    for ( int i = 1 ; i <= n ; ++ i ) {        sum[i] = sum[i - 1] + w[i] ;    }    for ( int i = 0 ; i < q ; ++ i ) {        scanf ( "%d%d" , &u , &v ) ;        pair < int , int > t1 = getval ( u , v ) ;        pair < int , int > t2 = make_pair ( - dp[u][0] - qp[v][0] , max ( dp[u][1] , qp[v][1] ) ) ;        pair < int , int > t3 = make_pair ( - dp[v][0] - qp[u][0] , max ( dp[v][1] , qp[u][1] ) ) ;        pair < int , int > t4 = make_pair ( - qp[v][0] - qp[u][0] - w[pos[1]] , max ( w[pos[1]] , max ( qp[v][1] , qp[u][1] ) ) ) ;        if ( t2 > t1 ) t1 = t2 ;        if ( t3 > t1 ) t1 = t3 ;        if ( t4 > t1 ) t1 = t4 ;        printf ( "%d %d\n" , -t1.first , t1.second ) ;    }}int main () {    int T ;    scanf ( "%d" , &T ) ;    for ( int i = 1 ; i <= T ; ++ i ) {        solve () ;    }    return 0 ;}