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Cod sursa(job #880953)
#include <fstream>
using namespace std;
ifstream in("aib.in");
ofstream out("aib.out");
struct AIB {
AIB(int);
~AIB() { delete[] c; }
void add(int, int);
int sum(int, int);
int minPos(int);
private:
int sumTo(int); // Suma din interv [1, pos]
int * c;
int N;
};
AIB::AIB(int n)
{
c = new int[n+1]; N = n;
for (int i = 1; i <= N; i++) c[i] = 0;
}
void AIB::add(int ind, int val)
{
int poz = 0;
while (ind <= N)
{
c[ind] += val;
while ( (ind & (1 << poz)) == 0 ) poz += 1;
ind += (1 << poz);
poz += 1;
}
}
int AIB::sumTo(int ind)
{
int sum = 0, poz = 0;
while (ind > 0)
{
sum += c[ind];
while ( (ind & (1 << poz)) == 0 ) poz += 1;
ind -= (1 << poz);
poz += 1;
}
return sum;
}
int AIB::sum(int a, int b)
{
return sumTo(b) - sumTo(a-1);
}
int AIB::minPos(int a)
{
int step;
for (step = 1; step < N; step = (step << 1));
for (int i = 0; step > 0; step = (step >> 1))
{
if (i + step <= N)
{
if (a >= c[i+step])
{
i += step; a -= c[i];
if (a == 0) return i;
}
}
}
return -1;
}
int main()
{
int n, m, x, y, op;
in >> n >> m;
AIB bin(n);
for (int i = 1; i <= n; i++)
{
in >> x;
bin.add(i, x);
}
for (int i = 1; i <= m; i++)
{
in >> op;
switch (op)
{
case 0: { in >> x >> y; bin.add(x, y); } break;
case 1: { in >> x >> y; out << bin.sum(x, y) << '\n'; } break;
case 2: {
in >> x;
out << bin.minPos(x) << '\n';
} break;
}
}
return 0;
}