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Cod sursa(job #975374)
#include<stdio.h>
#define maxn 100005
#define maxstep 1<<17
using namespace std;
int n,m;
int v[maxn],aib[maxn];
void update(int k,int val)
{
int i=0;
while(k<=n)
{
aib[k]+=val;
for(;((k>>i)&1)==0;i++);
k+=(1<<i);
i++;
}
}
int query(int k)
{
int sum=0,i=0;
while(k>0)
{
sum+=aib[k];
for(;((k>>i)&1)==0;i++);
k-=(1<<i);
i++;
}
return sum;
}
int search(int val)
{
int i,step=maxstep;
int sum=0;
for(i=0;step;step>>=1)
if(i+step<=n && val>=aib[i+step]+sum)
i+=step,sum+=aib[i];
if(sum==val && sum>0 ) return i;
return -1;
}
void read()
{
scanf("%d%d",&n,&m);
for(int i=1;i<=n;i++) {scanf("%d",&v[i]); update(i,v[i]);}
}
void solve()
{
int i;
int type,a,b;
for(i=1;i<=m;i++)
{
scanf("%d",&type);
if(type==0)
{
scanf("%d%d",&a,&b);
update(a,b);
}
else
if(type==1)
{
scanf("%d%d",&a,&b);
printf("%d\n",query(b)-query(a-1));
}
else
{
scanf("%d",&a);
printf("%d\n",search(a));
}
}
}
int main()
{
freopen("aib.in","r",stdin);
freopen("aib.out","w",stdout);
read();
solve();
fclose(stdin);
fclose(stdout);
return 0;
}