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Cod sursa(job #999275)
#include <iostream>
#include <fstream>
#define zeros(x) ((x^(x-1))&x)
using namespace std;
ifstream f("aib.in");
ofstream g("aib.out");
int n,m,v[100005],a[100005],s[100005];
void Update(int x,int nr)
{ int i;
for(i=x;i<=n;i+=zeros(i))
a[i]+=nr;
}
int Compute(int x)
{ int i,res=0;
for(i=x;i>=1;i-=zeros(i))
res+=a[i];
return res;
}
int Search(int x)
{ int i,l=1,r=n,mid,sum;
while(l<r)
{ mid=(l+r)/2;
sum=Compute(mid);
if (x<=sum) r=mid; else l=mid+1;
}
if (Compute(l)==x) return l;
return -1;
}
int main()
{ int i,t,x,y;
f>>n>>m;
for(i=1;i<=n;i++)
{f>>v[i];
s[i]=s[i-1]+v[i];
a[i]=s[i]-s[i-zeros(i)];
}
for(i=1;i<=m;i++)
{ f>>t;
if (t==0) { f>>x>>y; Update(x,y); }
if (t==1) { f>>x>>y; g<<Compute(y)-Compute(x-1)<<"\n"; }
if (t==2) { f>>x; g<<Search(x)<<"\n"; }
}
return 0;
}