一開始以爲區間樹狀數組沒什麼區別,xjb亂搞了後調了好久都調不出來QAQ
首先有一個差分數組di
d[i]=a[i]-a[i-1];
所以a[x]=d[1]+d[2]+…+d[x]
a[x]前綴和:d[1]x+d[2] (x-1)+…+ d[i] * (x-i+1)+…+ d[x] *1
維護 d[i] 和 d[i]*i
注意:
代碼中的e[i]不等於上文的d[i](其實是d[ i ]的樹狀數組)
f[i]不等於d[i]i(其實是 d[ i ] i 的樹狀數組)
codevs
Update(10月2日):
這個碼風太醜了,以下是我新的區間樹狀數組的部分代碼
void Ins(int x,int y){
for(int i=x;i<=n;i+=lb(i))f[i]+=y,g[i]+=x*y;
}
LL Sum(int x){
LL sum=0;
for(int i=x;i>=1;i-=lb(i))sum=(sum+(x+1)*f[i]-g[i]+mod)%mod;
return sum;
}
完整AC代碼(舊)
#include<cstdio>
#include<iostream>
#define N 200010
typedef long long LL;
using namespace std;
int n,m,o,p,q,x,y;
LL e[N],f[N];
int lowbit(int x){
return x&(-x);
}
void update(int x,int y){
int z=y*x;
while(x<=n){
f[x]+=z;
e[x]+=y;
x+=lowbit(x);
}
}
LL query(int x){
LL sum=0;
while(x>=1){
sum+=e[x];
x-=lowbit(x);
}
return sum;
}
LL Sum(int x){
LL sum=0;
while(x>=1){
sum+=f[x];
x-=lowbit(x);
}
return sum;
}
LL Solve(int p,int q){
return (q+1)*query(q)-Sum(q)+Sum(p-1)-p*query(p-1);
}
int main(){
freopen("data.txt","r",stdin);
scanf("%d",&n);
for(int i=1;i<=n;i++){
scanf("%d",&p);
update(i,p-q);
q=p;
}
scanf("%d",&m);
for(int i=1;i<=m;i++){
scanf("%d",&o);
if(o==1){
scanf("%d%d%d",&p,&q,&y);
update(p,y);
update(q+1,-y);
}
else if(o==2){
scanf("%d%d",&p,&q);
printf("%lld\n",Solve(p,q));
}
}
}