hdu 3911 线段树＋区间合并

来源：互联网发布：csmar数据库怎么用编辑：程序博客网时间：2024/06/05 03:23
模板题
#include <iostream>#include <cstdio>#include <algorithm>#include <cstring>#define MAX 100007using namespace std;int n,m;int a[MAX];struct Tree{    int l , r , lmx[2] , rmx[2] , mx[2] , lazy;}tree[MAX<<2];void push_up ( int u ){    for ( int i = 0 ; i < 2 ; i++ )    {        tree[u].lmx[i] = tree[u<<1].lmx[i];        tree[u].rmx[i] = tree[u<<1|1].rmx[i];        tree[u].mx[i] = max ( tree[u<<1].mx[i] , tree[u<<1|1].mx[i] );        if ( tree[u<<1].lmx[i] == tree[u<<1].r - tree[u<<1].l + 1 )            tree[u].lmx[i] = tree[u<<1].lmx[i] + tree[u<<1|1].lmx[i];        if ( tree[u<<1|1].rmx[i] == tree[u<<1|1].r - tree[u<<1|1].l + 1 )            tree[u].rmx[i] = tree[u<<1].rmx[i] + tree[u<<1|1].rmx[i];        tree[u].mx[i] = max ( tree[u].mx[i] , tree[u<<1].rmx[i] + tree[u<<1|1].lmx[i] );    }}void push_down ( int u ){    int lazy = tree[u].lazy;    if ( lazy&1 )    {        tree[u].lazy = 0;        tree[u<<1].lazy += lazy;        tree[u<<1|1].lazy += lazy;        swap ( tree[u<<1].lmx[0] , tree[u<<1].lmx[1] );        swap ( tree[u<<1].rmx[0] , tree[u<<1].rmx[1] );        swap ( tree[u<<1].mx[0] , tree[u<<1].mx[1] );        swap ( tree[u<<1|1].lmx[0] , tree[u<<1|1].lmx[1] );        swap ( tree[u<<1|1].rmx[0] , tree[u<<1|1].rmx[1] );        swap ( tree[u<<1|1].mx[0] , tree[u<<1|1].mx[1] );    }}void build ( int u , int l , int r ){    tree[u].l = l , tree[u].r = r;    tree[u].lazy = 0;    if ( l == r )    {        int c = a[l];        tree[u].lmx[c] = tree[u].rmx[c] = tree[u].mx[c] = 1;        tree[u].lmx[c^1] = tree[u].rmx[c^1] = tree[u].mx[c^1] = 0;        return;    }    int mid = l + r >> 1;    build ( u<<1 , l , mid );    build ( u<<1|1 , mid+1 , r );    push_up ( u );}void update ( int u , int left , int right ){    int l = tree[u].l , r = tree[u].r;    if ( left <= l && r <= right )    {        tree[u].lazy++;        swap ( tree[u].lmx[0] , tree[u].lmx[1] );        swap ( tree[u].rmx[0] , tree[u].rmx[1] );        swap ( tree[u].mx[0] , tree[u].mx[1] );        return;    }    push_down ( u );    int mid = l + r >> 1;    if ( left <= mid && right >= l )        update ( u<<1 , left , right );    if ( left <= r && right > mid )        update ( u<<1|1 , left , right );    push_up ( u );}struct Ret{    int mx,lmx,rmx,l,r;    Ret ( ) { }    Ret ( int a , int b , int c , int d  , int w )         : mx ( a ) , lmx ( b ) , rmx ( c ) , l ( d ) , r ( w ) { }};Ret query ( int u , int left , int right ){    int l = tree[u].l , r = tree[u].r;    if ( left <= l && r <= right )        return Ret ( tree[u].mx[1] , tree[u].lmx[1] , tree[u].rmx[1] , tree[u].l , tree[u].r );    int mid = l + r >> 1;    push_down ( u );    if ( mid < left ) return query ( u<<1|1 , left , right );    else if ( right <= mid ) return query ( u<<1 , left , right );    else    {        Ret ret1 = query ( u<<1 , left , right );        Ret ret2 = query ( u<<1|1 , left , right );        Ret ret;        ret.l = ret1.l , ret.r = ret2.r;        ret.mx = max ( ret1.mx , ret2.mx );        ret.lmx = ret1.lmx;        ret.rmx = ret2.rmx;        if ( ret1.lmx == ret1.r - ret1.l + 1 )            ret.lmx = ret1.lmx + ret2.lmx;        if ( ret2.rmx == ret2.r - ret2.l + 1 )            ret.rmx = ret2.rmx + ret1.rmx;        ret.mx = max ( ret.mx , ret1.rmx + ret2.lmx );        return ret;    }}int main ( ){    while ( ~scanf ( "%d" , &n ) )    {        for ( int i = 1 ; i <= n ; i++ ) scanf ( "%d" , &a[i] );        scanf ( "%d" , &m );        int f,l,r;        build ( 1, 1 ,n );        for ( int i = 0 ; i < m ; i++ )        {            scanf ( "%d%d%d" , &f , &l , &r );            if ( f ) update ( 1 , l , r );            else printf ( "%d\n" , query ( 1 , l , r ).mx );        }    }}
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