Cod sursa(job #2694166)

Utilizator cyg_dawidDavid Ghiberdic cyg_dawid Data 8 ianuarie 2021 12:43:33
Problema Arbori indexati binar Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.21 kb
#include <fstream>

using namespace std;

ifstream fin("aib.in");
ofstream fout("aib.out");
int const nmax = 100000;
int aib[nmax + 5];
int n;

void update(int poz, int val) {
    while(poz <= n) {
        aib[poz] += val;
        poz += (poz ^ (poz & (poz - 1)));
    }
}

int query(int poz) {
    int sum = 0;
    while(0 < poz) {
        sum += aib[poz];
        poz = poz & (poz - 1);
    }
    return sum;
}

int bs(int target) {
    int st = 1, dr = n + 1;
    while(st < dr) {
        int med = (st + dr) >> 1;
        if(query(med) < target)
            st = med + 1;
        else
            dr = med;
    }
    if(query(dr) != target)
        return -1;
    return dr;
}

int main()
{
    int m;
    fin >> n >> m;
    for(int i = 1; i <= n; i++) {
        int var;
        fin >> var;
        update(i, var);
    }
    while(m--) {
        int tip, a, b;
        fin >> tip;
        if(tip == 0) {
            fin >> a >> b;
            update(a, b);
        } else if(tip == 1) {
            fin >> a >> b;
            fout << query(b) - query(a - 1) << "\n";
        } else {
            fin >> a;
            fout << bs(a) << "\n";
        }
    }
    return 0;
}