BZOJ 3626: [LNOI2014]LCA( 树链剖分 + 离线 )
说多了都是泪啊...调了这么久..
离线可以搞 , 树链剖分就OK了...
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#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
#define rep( i , n ) for( int i = 0 ; i < n ; ++i )
#define clr( x , c ) memset( x , c , sizeof( x ) )
#define Rep( i , n ) for( int i = 1 ; i <= n ; ++i )
#define REP( x ) for( edge* e = head[ x ] ; e ; e = e -> next )
#define mod( x ) ( ( x ) %= MOD )
#define M( l , r ) ( ( l + r ) >> 1 )
#define L( x ) ( ( x ) << 1 )
#define R( x ) ( L( x ) ^ 1 )
using namespace std;
const int maxn = 50000 + 5;
const int maxnode = 140000;
const int MOD = 201314;
int n;
struct edge {
int to;
edge* next;
};
edge* pt , EDGE[ maxn ];
edge* head[ maxn ];
inline void add_edge( int u , int v ) {
pt -> to = v;
pt -> next = head[ u ];
head[ u ] = pt++;
}
void edge_init() {
pt = EDGE;
clr( head , 0 );
}
int top[ maxn ] , fa[ maxn ] , son[ maxn ] , size[ maxn ];
void dfs( int x ) {
size[ x ] = 1;
REP( x ) {
int to = e -> to;
dfs( to );
size[ x ] += size[ to ];
if( son[ x ] == -1 || size[ to ] > size[ son[ x ] ] )
son[ x ] = to;
}
}
int id[ maxn ] , id_cnt = 0;
int TOP;
void DFS( int x ) {
id[ x ] = ++id_cnt;
top[ x ] = TOP;
if( son[ x ] != -1 )
DFS( son[ x ] );
REP( x ) if( e -> to != son[ x ] )
DFS( TOP = e -> to );
}
void DFS_init() {
clr( son , -1 );
dfs( 0 );
DFS( TOP = 0 );
}
int add[ maxnode ] , sum[ maxnode ];
int L , R , query_ans;
inline void maintain( int x , int l , int r ) {
sum[ x ] = add[ x ] * ( r - l + 1 );
if( r > l )
sum[ x ] += sum[ L( x ) ] + sum[ R( x ) ];
}
void update( int x , int l , int r ) {
if( L <= l && r <= R )
add[ x ]++;
else {
int m = M( l , r );
if( L <= m ) update( L( x ) , l , m );
if( m < R) update( R( x) , m + 1 , r );
}
maintain( x , l , r );
}
inline void Update( int l , int r ) {
L = l , R = r;
update( 1 , 1 , n );
}
void query( int x , int l , int r , int Add ) {
if( L <= l && r <= R )
query_ans += sum[ x ] + Add * ( r - l + 1 );
else {
Add += add[ x ];
int m = M( l , r );
if( L <= m ) query( L( x ) , l , m , Add );
if( m < R ) query( R( x ) , m + 1 , r , Add );
}
}
inline int Query( int l , int r ) {
query_ans = 0;
L = l , R = r;
query( 1 , 1 , n , 0 );
return query_ans;
}
int Q( int x ) {
int res = 0;
while( top[ x ] != top[ 0 ] ) {
mod( res += Query( id[ top[ x ] ] , id[ x ] ) );
x = fa[ top[ x ] ];
}
return ( res + Query( id[ 0 ] , id[ x ] ) ) % MOD;
}
void modify( int x ) {
while( top[ x ] != top[ 0 ] ) {
Update( id[ top[ x ] ] , id[ x ] );
x = fa[ top[ x ] ];
}
Update( id[ 0 ] , id[ x ] );
}
struct data {
int x , num , s;
bool operator < ( const data &rhs ) const {
return x < rhs.x;
}
};
data A[ maxn << 1 ];
int z[ maxn ];
int ans[ maxn ];
int read() {
int ans = 0;
char c = getchar();
while( ! isdigit( c ) ) c = getchar();
while( isdigit( c ) ) {
ans = ans * 10 + c - '0';
c = getchar();
}
return ans;
}
int main() {
freopen( "test.in" , "r" , stdin );
n = read();
int q = read();
edge_init();
Rep( i , n - 1 ) {
fa[ i ] = read();
add_edge( fa[ i ] , i );
}
rep( i , q ) {
data &a = A[ i ] , &b = A[ i + q ];
a.x = read() , b.x = read();
*( z + i ) = read();
a.x--;
a.s = -1 , b.s = 1;
a.num = b.num = i;
}
DFS_init();
clr( sum , 0 );
q <<= 1;
sort( A , A + q );
int cur = 0;
clr( ans , 0 );
for( ; cur < q && A[ cur ].x < 0 ; cur++ );
rep( i , n ) {
modify( i );
for( ; cur < q , A[ cur ].x == i ; cur++ )
mod( mod( ans[ A[ cur ].num ] += Q( z[ A[ cur ].num ] ) * A[ cur ].s ) += MOD );
}
q >>= 1;
rep( i , q )
printf( "%d\n" , ans[ i ] );
return 0;
}
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3626: [LNOI2014]LCA
Time Limit: 10 Sec Memory Limit: 128 MBSubmit: 855 Solved: 291
[Submit][Status][Discuss]
Description
给出一个n个节点的有根树（编号为0到n-1，根节点为0）。一个点的深度定义为这个节点到根的距离+1。
设dep[i]表示点i的深度，LCA(i,j)表示i与j的最近公共祖先。
有q次询问，每次询问给出l r z，求sigma_{l<=i<=r}dep[LCA(i,z)]。
（即，求在[l,r]区间内的每个节点i与z的最近公共祖先的深度之和）
Input
第一行2个整数n q。
接下来n-1行，分别表示点1到点n-1的父节点编号。
接下来q行，每行3个整数l r z。
Output
输出q行，每行表示一个询问的答案。每个答案对201314取模输出
Sample Input
5 2
0
0
1
1
1 4 3
1 4 2
0
0
1
1
1 4 3
1 4 2
Sample Output
8
5
5
HINT
共5组数据，n与q的规模分别为10000,20000,30000,40000,50000。
Source
