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Cod sursa(job #2769444)

Utilizator bubblegumixUdrea Robert bubblegumix 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';
			}
	
	}
	
}