Cod sursa(job #1139919)

Utilizator manutrutaEmanuel Truta manutruta Data 11 martie 2014 16:53:00
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.79 kb
#include <iostream>
#include <fstream>

using namespace std;

#define MAXN 100005

FILE *fin=fopen("arbint.in", "r");

unsigned const maxb=8192;
char buf[maxb];
int ptr=maxb-1;

int getInt()
{
    int nr=0;
    while(buf[ptr]>'9' || buf[ptr]<'0')
    {
        if(++ptr>=maxb)
            fread(buf, maxb, 1, fin), ptr=0;
    }
    while(buf[ptr]<='9' && buf[ptr]>='0')
    {
        nr=nr*10+buf[ptr]-'0';
        if(++ptr>=maxb)
            fread(buf, maxb, 1, fin), ptr=0;
    }

    return nr;
}
FILE* g = fopen("arbint.out", "w");

int n, m, sol;
int AINT[3 * MAXN];

void update(int nod, int st, int dr, int pos, int nr)
{
    if (st == dr)
    {
        AINT[nod] = nr;
        return;
    }

    int mij = ((st + dr) >> 1);

    if (pos <= mij) {
        update((nod << 1), st, mij, pos, nr);
    } else {
        update((nod << 1) + 1, mij + 1, dr, pos, nr);
    }

    AINT[nod] = max(AINT[2 * nod], AINT[2 * nod + 1]);
}

void query(int nod, int st, int dr, int a, int b)
{
    if (a <= st && dr <= b) {
        sol = max(sol, AINT[nod]);
        return;
    }

    int mij = ((st + dr) >> 1);
    if (a <= mij) {
        query((nod << 1), st, mij, a, b);
    }
    if (b > mij) {
        query((nod << 1) + 1, mij + 1, dr, a, b);
    }
}

int main()
{
    n = getInt(); m = getInt();
    for (int i = 1; i <= n; i++) {
        int x; x = getInt();
        update(1, 1, n, i, x);
    }

    for (int i = 1; i <= m; i++) {
        int op, a, b;
        op = getInt(); a = getInt(); b = getInt();

        if (op == 1) {
            update(1, 1, n, a, b);
        } else {
            sol = 0;
            query(1, 1, n, a, b);
            fprintf(g, "%d\n", sol);
        }
    }

    fclose(fin);
    fclose(g);
    return 0;
}