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Cod sursa(job #431008)
#include <fstream>
using namespace std;
#define MAXN 100005
fstream fin("aib.in",ios::in);
fstream fout("aib.out",ios::out);
int c[MAXN],n,m;
void update(int ind,int val){
int poz=0;
while(ind<=n){
c[ind]+=val;
while(!(ind&(1<<poz))){
poz++;
}
ind+=(1<<poz);
poz++;
}
}
int query(int ind){
int s=0,poz=0;
while(ind>0){
s+=c[ind];
while(!(ind&(1<<poz))){
poz++;
}
ind-=(1<<poz);
poz++;
}
return s;
}
int search(int sum){
int pos=n+1,end=n+1,beg=0,mdl=n,s;
s=query(mdl);
if(s==sum){
pos=n;
}
while(mdl){
mdl=beg+((end-beg)>>1);
s=query(mdl);
if(s>sum){
if(end>mdl){
end=mdl;
}
mdl--;
}else if(s==sum){
pos=((pos<mdl)?pos:mdl);
end=mdl;
mdl--;
}else{
if(beg<mdl){
beg=mdl;
}
mdl++;
}
if(mdl<=beg)break;
if(mdl>=end)break;
}
return ((pos==n+1)?-1:pos);
}
int main(){
int op,a,b,d;
fin>>n>>m;
for(int i=1;i<=n;i++){
fin>>d;
update(i,d);
}
for(int i=0;i<m;i++){
fin>>op>>a;
switch(op){
case 0:
fin>>b;
update(a,b);
break;
case 1:
fin>>b;
fout<<query(b)-query(a-1);
break;
case 2:
fout<<search(a);
break;
}
}
return 0;
}