Cod sursa(job #2578487)

Utilizator vlad082002Ciocoiu Vlad vlad082002 Data 11 martie 2020 10:18:57
Problema Arbori indexati binar Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.1 kb
#include <fstream>
using namespace std;

ifstream fin("aib.in");
ofstream fout("aib.out");

int aib[100005], n, m, t, a, b;

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

int query(int poz) {
    int s = 0;
    while(poz > 0) {
        s += aib[poz];
        poz -= (poz&-poz);
    }
    return s;
}

int cb(int val) {
    int st = 1, dr = n;
    while(st <= dr) {
        int m = (st+dr)/2;
        int q = query(m);
        if(q == val && query(m-1) < val)
            return m;
        else if(q >= val)
            dr = m-1;
        else
            st = m+1;
    }
    return -1;
}

int main() {
    fin >> n >> m;
    for(int i = 1; i <= n; i++) {
        fin >> a;
        update(i, a);
    }
    while(m--) {
        fin >> t;
        if(t == 0) {
            fin >> a >> b;
            update(a, b);
        } else if(t == 1) {
            fin >> a >> b;
            fout << query(b) - query(a-1) << '\n';
        } else {
            fin >> a;
            fout << cb(a) << '\n';
        }
    }
}