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cp-templates/trees/segtree.old.cc

43 lines
1.0 KiB
C++

constexpr int MAXN=1e5+10;
int a[MAXN],d[4*MAXN],b[4*MAXN]; // tree d, tags b
void build(int s,int t,int p){ // root p, range [s,t]
if(s==t){
d[p]=a[s];
return;
}
int m=s+(t-s>>1);
build(s,m,p*2),build(m+1,t,p*2+1);
d[p]=d[p*2]+d[p*2+1];
}
int getsum(int s,int t,int p,int l,int r){
if(l<=s&&t<=r)return d[p];
int m=s+(t-s>>1),sum=0;
if(b[p]){
d[p*2]+=b[p]*(m-s+1),d[p*2+1]+=b[p]*(t-m);
b[p*2]+=b[p],b[p*2+1]+=b[p];
b[p]=0;
}
if(l<=m)sum+=getsum(s,m,p*2,l,r);
if(r>m) sum+=getsum(m+1,t,p*2+1,l,r);
return sum;
}
void update(int s,int t,int p,int l,int r,int c) { // difference c
// replace `+=` with `=` to implement modifications
if(l<=s&&t<=r){
d[p]+=(t-s+1)*c,b[p]+=c;
return;
}
int m=s+(t-s>>1);
if(b[p]&&s!=t){
d[p*2]+=b[p]*(m-s+1),d[p*2+1]+=b[p]*(t-m);
b[p*2]+=b[p],b[p*2+1]+=b[p];
b[p]=0;
}
if(l<=m)update(s,m,p*2,l,r,c);
if(r>m) update(m+1,t,p*2+1,l,r,c);
d[p]=d[p*2]+d[p*2+1];
}