Qiita Teams that are logged in
You are not logged in to any team

Community
Service
Qiita JobsQiita ZineQiita Blog
2
Help us understand the problem. What is going on with this article?
@hotman78

# 【競プロ】セグ木は2冪で配列を取らなくていいという話と30行実装

More than 1 year has passed since last update.

# えびちゃんありがとうの章

f(s,node[--r]);をf(node[--r],s);に変えると可換性を要求せずにすむらしいです(凄い)

# 実装

segment.cpp
``````template<typename T>
struct segment{
vector<T> node;
int n;
segment(int n):n(n){node.assign(n*2,e);}
T get(int l,int r){
l+=n;r+=n;
T s=e,t=e;
while(l<r){
if(l&1)s=f(s,node[l++]);
if(r&1)t=f(node[--r],t);
l/=2;r/=2;
}
return f(s,t);
}
void update(int t,T x){
t+=n;
node[t]=f(node[t],x);
while(t>1)t/=2,node[t]=f(node[t*2],node[t*2+1]);
}
void change(int t,T x){
t+=n;
node[t]=x;
while(t>1)t/=2,node[t]=f(node[t*2],node[t*2+1]);
}
T e={1,0};
T f(const T& s,const T& t){
return {t.first*s.first,t.first*s.second+t.second};
}
};
``````

# verify

2
Help us understand the problem. What is going on with this article?
Why not register and get more from Qiita?
1. We will deliver articles that match you
By following users and tags, you can catch up information on technical fields that you are interested in as a whole
2. you can read useful information later efficiently
By "stocking" the articles you like, you can search right away