poj3468 (line segment tree interval update)

topic link

Problem solving instructions:

Naked Question Template

ac code:

#include<iostream>
#include<algorithm>
#include<string>
using namespace std;
const int MAXN=1e5+10;
typedef long long ll;
ll s[MAXN<<2],col[MAXN<<2];
void up(int p){
	s[p]=s[p*2]+s[p*2+1];
}
void down(int p,int l,int r){
	if(col[p]){
		int mid=(l+r)/2;
		s[p*2]+=(ll)col[p]*(mid-l+1);
		s[p*2+1]+=(ll)col[p]*(r-mid);
		col[p*2]+=col[p];
		col[p*2+1]+=col[p];
		col[p]=0;
	}
}
void modify(int p,int l,int r,int x,int y,ll c){
	if(x<=l&&y>=r){
		s[p]+=(ll)c*(r-l+1);
		col[p]+=(ll)c;
		return;
	}
	down(p,l,r);
	int mid=(l+r)/2;
	if(x<=mid){
		modify(p*2,l,mid,x,y,c);
	}
	if(y>mid){
		modify(p*2+1,mid+1,r,x,y,c);
	}
	up(p);
}
ll query(int p,int l,int r,int x,int y){
	if(x<=l&&y>=r){
		return s[p];
	}
	down(p,l,r);
	int mid=(l+r)/2;
	ll res=0;
	if(x<=mid){
		res+=query(p*2,l,mid,x,y);
	}
	if(y>mid){
		res+=query(p*2+1,mid+1,r,x,y);
	}
	return res;
}
int main(){
	int n,m;
	ios::sync_with_stdio(false);
	cin>>n>>m;
	int ip1,ip2;
	ll ip3;
	for(int i=1;i<=n;i++){
		cin>>ip1;
		modify(1,1,n,i,i,ip1);
	}
	string op;
	for(int i=1;i<=m;i++){
		cin>>on;
		if(op=="Q"){
			cin>>ip1>>ip2;
			cout<<query(1,1,n,ip1,ip2)<<endl;
		}
		else {
			cin>>ip1>>ip2>>ip3;
			modify(1,1,n,ip1,ip2,ip3);
		}
	}
	return 0;
}