Cod sursa(job #1806368)

Utilizator adystar00Bunea Andrei adystar00 Data 15 noiembrie 2016 10:59:23
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.69 kb
#include <iostream>
#include <fstream>
#include <algorithm>
#include <vector>
#include <cstring>
#include <cmath>
using namespace std;
int n,v[400010],aib[400010],answer;
const int INF = 1000010;
void recalculate(int node)
{
    aib[node]=max(aib[2*node],aib[2*node+1]);
}
void build (int node, int left, int right)
{
    if(left==right)
        aib[node]=v[left];
    else
    {
        int mij = (left+right)/2;
        build(2*node,left,mij);
        build(2*node+1,mij+1,right);
        recalculate(node);
    }
}
void update (int node, int left, int right,int x, int y)
{
    if(right==left)
        aib[node]=y;
    else
    {
        int mij = (left+right)/2;
        if(mij>=x)
            update(2*node,left,mij,x,y);
        else
            update(2*node+1,mij+1,right,x,y);
            recalculate(node);
    }
}
int query (int node,int left, int right, int x, int y)
{
    if(x<=left && y>=right)
        return aib[node];
    else
    {
        int answer = -INF;
        int mij = (left+right)/2;
        if(x<=mij)
            answer = max(answer , query(2*node,left,mij,x,y));
        if(y>=mij+1)
            answer = max(answer , query(2*node+1,mij+1,right,x,y));
    return answer;
    }
}
int main()
{
    ifstream fin ("arbint.in");
    ofstream fout ("arbint.out");
    int m,i,a,q,x,y;
    fin>>n>>m;
    for(i=1; i<=n; i++)
        fin>>v[i];
    build(1,1,n);
    for(q=1; q<=m; q++)
    {
        fin>>a;
        if(a==1)
        {
            fin>>x>>y;
            update(1,1,n,x,y);
        }
        if(a==0)
        {
            fin>>x>>y;
            fout<<query(1,1,n,x,y)<<"\n";
        }
    }
    return 0;
}