Mai intai trebuie sa te autentifici.
Cod sursa(job #2769444)
Utilizator | Data | 15 august 2021 18:43:44 | |
---|---|---|---|
Problema | Arbori indexati binar | Scor | 0 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 1.01 kb |
#include<fstream>
#define lsb(x) (x&(-x))
#define NMAX 100010
using namespace std;
int aib[NMAX];
int a[NMAX];
int n, m;
ifstream f("aib.in");
ofstream g("aib.out");
void update_aib(int poz, int val)
{
int i;
for (i = poz; i <= n; i += lsb(i))
aib[i] += val;
}
int query(int x)
{
int i, sum=0;
for (i = x; i > 0; i -= lsb(i))
sum += aib[i];
return sum;
}
int findsum(int s)
{
int st = 1, dr = n;
while (st <= dr)
{
int m = (st + dr) / 2;
if (query(m) <= s)
{
st = m + 1;
if (query(m) == s)
return m;
}
else
dr = m - 1;
}
}
int main()
{
f >> n >> m;
for (int i = 1; i <= n; i++)
f >> a[i];
for (int i = 1; i <= n; i++)
update_aib(i, a[i]);
for (int i = 1; i <= m; i++)
{
int op, a, b;
f >> op;
if (op == 0)
{
f >> a >> b;
update_aib(a, b);
}
else
if (op == 1)
{
f >> a >> b;
g << query(b) - query(a - 1) << '\n';
}
else
{
f >> a;
g << findsum(a) << '\n';
}
}
}