P2710 数列[fhq treap]

调了一辈子的fhq treap…

如果不会最大子段和

如果不会fhq treap

7个操作…
其中三个查询 单点查询其实可以和区间查询写成一个（

fhq treap 的修改操作大概就是 \(split\) 完了然后把修改区间的根 打上标记 等着下传就完事了…

那这题没了…我给个好一点的小数据…反正我照着这个调了挺久的…

.in
50 10
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
GET 13
REVERSE 15 1
MAKE-SAME 1 1 3
REVERSE 21 8
GET-SUM 22 3
MAX-SUM 32 2
GET 8
DELETE 4 9
GET 36
REVERSE 34 2

.out
13
78
65
8
45

#include<cstdio>
#include<cstdlib>
#include<string>
#include<iostream>
int min(int x , int y) {
    return x < y ? x : y ;
}
int max(int x , int y) {
    return x > y ? x : y ;
}
void swap(int & x , int & y) {
    x ^= y ^= x ^= y ;
}

int read() {
    int x = 0 , f = 1 ;
    char c = getchar() ;
    while(c < 48 || c > 57) {
        if(c == '-') f = 0 ;
        c = getchar() ;
    }
    while(c >= 48 && c <= 57) {
        x = (x << 1) + (x << 3) + (c & 15) ;
        c = getchar() ;
    }
    return f ? x : -x ;
}

int n , m , rt , cnt ;
constexpr int N = 2e6 + 10 ;
constexpr int lim = 2333 ;
int a[N] ;
int rnd[N] , val[N] , sum[N] , sz[N] , ls[N] , rs[N] ;
int lmax[N] , rmax[N] , mx[N] ;
int tag[N] , rev[N] ;

void pushup(int o) {
    sz[o] = sz[ls[o]] + sz[rs[o]] + 1 ;
    sum[o] = sum[ls[o]] + sum[rs[o]] + val[o] ;
    lmax[o] = max(lmax[ls[o]] , sum[ls[o]] + max(0 , lmax[rs[o]]) + val[o]) ;
    rmax[o] = max(rmax[rs[o]] , sum[rs[o]] + max(0 , rmax[ls[o]]) + val[o]) ;
    mx[o] = max(0 , rmax[ls[o]]) + max(0 , lmax[rs[o]]) + val[o] ;
    if(ls[o]) mx[o] = max(mx[o] , mx[ls[o]]) ;
    if(rs[o]) mx[o] = max(mx[o] , mx[rs[o]]) ;
}

void reverse(int o) {
    swap(ls[o] , rs[o]) ;
    swap(lmax[o] , rmax[o]) ;
    rev[o] ^= 1 ;
}

void cover(int o , int v) {
    val[o] = tag[o] = v ;
    sum[o] = v * sz[o] ;
    lmax[o] = rmax[o] = mx[o] = max(sum[o] , v) ;
}

void pushdown(int o) {
    if(rev[o]) {
        if(ls[o]) reverse(ls[o]) ;
        if(rs[o]) reverse(rs[o]) ;
        rev[o] ^= 1 ;
    }
    if(tag[o] != lim) {
        if(ls[o]) cover(ls[o] , tag[o]) ;
        if(rs[o]) cover(rs[o] , tag[o]) ;
        tag[o] = lim ;
    }
}

int newnode(int k) {
    ++ cnt ;
    rnd[cnt] = rand() ;
    val[cnt] = sum[cnt] = k ;
    lmax[cnt] = rmax[cnt] = mx[cnt] = k ;
    sz[cnt] = 1 ;
    tag[cnt] = lim ;
    ls[cnt] = rs[cnt] = 0 ;
    return cnt ;
}

int merge(int x , int y) {
    if(! x || ! y) return x | y ;
    if(rnd[x] < rnd[y]) {
        pushdown(x) ;
        rs[x] = merge(rs[x] , y) ;
        pushup(x) ;
        return x ;
    } else {
        pushdown(y) ;
        ls[y] = merge(x , ls[y]) ;
        pushup(y) ;
        return y ;
    }
}

void split(int cur , int k , int & x , int & y) {
    if(! cur) {
        x = y = 0 ;
        return ;
    }
    pushdown(cur) ;
    if(sz[ls[cur]] < k) {
        split(rs[cur] , k - sz[ls[cur]] - 1 , x , y) ;
        rs[cur] = 0 ;
        pushup(cur) ;
        x = merge(cur , x) ;
    } else {
        split(ls[cur] , k , x , y) ;
        ls[cur] = 0 ;
        pushup(cur) ;
        y = merge(y , cur) ;
    }
}

int newrt(int len) {
    int _newrt = 0 ;
    for(int i = 1 ; i <= len ; i ++) _newrt = merge(_newrt , newnode(read())) ;
    return _newrt ;
}

void insert(int pos , int len) {
    int x , y ;
    split(rt , pos , x , y) ;
    rt = merge(merge(x , newrt(len)) , y) ;
}

void remove(int l , int r) {
    int x , y , z ;
    split(rt , l - 1 , x , z) ;
    split(z , r - l + 1 , y , z) ;
    rt = merge(x , z) ;
}

void rever(int l , int r) {
    int x , y , z ;
    split(rt , l - 1 , x , z) ;
    split(z , r - l + 1 , y , z) ;
    reverse(y) ;
    rt = merge(merge(x , y) , z) ;
}

void cover(int l , int r , int v) {
    int x , y , z ;
    split(rt , l - 1 , x , z) ;
    split(z , r - l + 1 , y , z) ;
    cover(y , v) ;
    rt = merge(merge(x , y) , z) ;
}

int query_sum(int l , int r) {
    int x , y , z ;
    split(rt , l - 1 , x , z) ;
    split(z , r - l + 1 , y , z) ;
    int res = sum[y] ;
    rt = merge(merge(x , y) , z) ;
    return res ;
}

int query_point(int pos) {
    int x , y , z ;
    split(rt , pos , x , z) ;
    split(x , pos - 1 , x , y) ;
    int res = val[y] ;
    rt = merge(merge(x , y) , z) ;
    return res ;
}

int query_max_sum(int l , int r) {
    int x , y , z ;
    split(rt , l - 1 , x , z) ;
    split(z , r - l + 1 , y , z) ;
    int res = mx[y] ;
    rt = merge(merge(x , y) , z) ;
    return res ;
}

int getopt(std :: string opt) {
    if(opt == "INSERT") return 1 ;
    if(opt == "DELETE") return 2 ;
    if(opt == "REVERSE") return 3 ;
    if(opt == "MAKE-SAME") return 4 ;
    if(opt == "GET-SUM") return 5 ;
    if(opt == "GET") return 6 ;
    if(opt == "MAX-SUM") return 7 ;
}

int main() {
    srand(19260817) ;
    n = read() , m = read() ;
    rt = newrt(n) ;
    while(m --) {
        std :: string s ;
        std :: cin >> s ;
        int opt = getopt(s) ;
        if(opt == 1) {
            int pos = read() , len = read() ;
            insert(pos , len) ;
        }
        if(opt == 2) {
            int pos = read() , len = read() ;
            remove(pos , pos + len - 1) ;
        }
        if(opt == 3) {
            int pos = read() , len = read() ;
            rever(pos , pos + len - 1) ;
        }
        if(opt == 4) {
            int pos = read() , len = read() , v = read() ;
            cover(pos , pos + len - 1 , v) ;
        }
        if(opt == 5) {
            int pos = read() , len = read() ;
            printf("%d\n" , query_sum(pos , pos + len - 1)) ;
        }
        if(opt == 6) printf("%d\n" , query_point(read())) ;
        if(opt == 7) {
            int pos = read() , len = read() ;
            printf("%d\n" , query_max_sum(pos , pos + len - 1)) ;
        }
    }
    return 0 ;
}

原文地址：https://www.cnblogs.com/Isaunoya/p/12005555.html