Cod sursa(job #2786364)

Utilizator Robys01Robert Sorete Robys01 Data 20 octombrie 2021 19:51:43
Problema Arbori indexati binar Scor 40
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.22 kb
#include <bits/stdc++.h>

using namespace std;

int n, m, tree[100001];

void make() {

    for(int i = 1; i <= n; i++) {
        int p = i + (i & -i);
        if(p <= n)
            tree[p] += tree[i]; 
    }
}

int sum(int i) {
    int suma = 0;
    while(i > 0) {
        suma += tree[i];
        i -= i&-i;
    }
    return suma;
}

void add(int i, int x) {
    while(i <= n) {
        tree[i] += x;
        i += i&-i; 
    }
}

int main()
{
    freopen("aib.in", "r", stdin);
    freopen("aib.out", "w", stdout);

    cin>>n>>m;
    for(int i = 1; i<=n; i++)
        cin>>tree[i];

    make();

    int x, y;
    
    for(; m; --m) {
        short c; cin>>c;
        if(c == 0) {
            cin>>x>>y;
            add(x, y);
        }
        if(c == 1) {
            cin>>x>>y;
            cout<<sum(y) - sum(x - 1)<<'\n';
        }
        if(c == 2) {
            cin>>x;
            int p = 0;
            for(int pas = n/2; pas; pas/=2)
                while(p + pas <= n && sum(p + pas) <= x)
                    p += pas;

            if(sum(p) == x)
                cout<<p<<'\n';
            else
                cout<<-1<<'\n';   
        }
    }
    return 0;
}