Cod sursa(job #2841318)

Utilizator Chiri_Robert Chiributa Chiri_ Data 29 ianuarie 2022 15:40:21
Problema Arbori indexati binar Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.35 kb
#include <bits/stdc++.h>

using namespace std;

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

int n, m, x[100001];
int t, a, b;
int aib[100001];
int sp[100001];

void generare() {
    for (int i = 1; i <= n; i++) {
        aib[i] = sp[i] - sp[i & (i - 1)];
    }
}

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

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

int caut(int k) {
    int st = 1, sf = n, mij;
    while (st < sf) {
        int mij = (st + sf) / 2;
        int s = sum(mij);
        if (s == k) {
            return mij;
        } else if (s < k) {
            st = mij + 1;
        } else {
            sf = mij;
        }
    }
    return st;
}

int main() {
    fin >> n >> m;
    for (int i = 1; i <= n; i++) {
        fin >> x[i];
        sp[i] = sp[i - 1] + x[i];
    }
    generare();

    for (int i = 0; i < m; i++) {
        fin >> t;
        switch (t) {
            case 0:
                fin >> a >> b;
                add(a, b);
                break;

            case 1:
                fin >> a >> b;
                fout << sum(b) - sum(a - 1) << '\n';
                break;
            case 2:
                fin >> a;
                fout << caut(a) << '\n';
                break;
        }
    }
}