Cod sursa(job #2221852)

Utilizator inquisitorAnders inquisitor Data 16 iulie 2018 00:00:41
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.97 kb
#include <stdio.h>
#include <ctype.h>

const int BUFFSIZE = 1024;
const int MAX_N = 100000;

int fen[MAX_N + 1];
char buff[BUFFSIZE];
int ptr = BUFFSIZE;

int n;

inline char getChr()
{
    if (ptr == BUFFSIZE)
    {
        fread(buff, 1, BUFFSIZE, stdin);
        ptr = 0;
    }
    return buff[ ptr ++ ];
}

inline int readInt()
{
    register int q = 0;
    char c;

    do
    {
        c = getChr();
    } while ( ! isdigit( c ) );
    do
    {
        q = (q << 1) + (q << 3) + (c - '0');
        c = getChr();
    } while ( isdigit( c ) );
    return q;
}

inline void fenwickAdd(int pos, const int &x)
{
    for (; pos <= n; pos += (pos & -pos))
        fen[pos] += x;
}

inline int fenwickSum(int pos)
{
    int s = 0;
    for (; pos; pos &= (pos - 1))
        s += fen[ pos ];
    return s;
}

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

    n = readInt();
    m = readInt();
    for (int i = 1; i <= n; i++)
    {
        x = readInt();
        fenwickAdd(i, x);
    }
    for (int i = 0; i < m; i++)
    {
        type = readInt();
        x = readInt();
        if (type == 2)
        {
            int pos = 0;
            int interval = (1 << (31 - __builtin_clz(n)));
            while (interval && x)
            {
                if ((interval + pos <= n) && (fen[interval + pos] <= x))
                {
                    pos += interval;
                    x -= fen[pos];
                }
                interval >>= 1;
            }
            if (!x && pos)
                printf("%d\n", pos);
            else
                puts("-1");
        }
        else
        {
            y = readInt();
            if (!type)
                fenwickAdd(x, y);
            else
                printf("%d\n", fenwickSum(y) - fenwickSum(x - 1));
        }
    }
    fclose(stdin);
    fclose(stdout);
    return 0;
}