Cod sursa(job #2798179)

Utilizator casiannCasian casiann Data 10 noiembrie 2021 23:25:46
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.4 kb
#include <bits/stdc++.h>
using namespace std;
 
#define NMAX 100001

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

int n, m, tree[4*NMAX+1], v[NMAX];
 
void update(int node, int st, int dr, int poz, int val){
    if(st == dr){
        tree[node] = val;
        return;
    }
    int mij = (dr+st)/2;
    if(poz<=mij)
        update(2*node, st, mij, poz, val);
    else update(2*node+1, mij+1,dr, poz, val);
    tree[node] = max(tree[2*node], tree[2*node+1]);
}

void build(int node, int st, int dr){
    if(st == dr){
        tree[node] = v[st];
        return;
    }
    int mij = (dr+st)/2;
    build(2*node, st, mij);
    build(2*node +1, mij+1,dr);
    tree[node] = max(tree[2*node], tree[2*node+1]);
}

int query(int node, int st, int dr, int a, int b){
    if(a <= st && dr <= b){
        return tree[node];
    }
    int mij = (st+dr)/2;
    int ans1=0, ans2=0;
    if(a<=mij)
        ans1 = query(2*node, st, mij, a,b);
    if(b>mij)
        ans2 = query(2*node+1, mij+1, dr, a,b);
    return max(ans1,ans2);
}

int main(){
    fin >> n >> m;
    for(int i=1; i<=n; i++){
        fin >> v[i];
    }
    build(1,1,n);
    for(int i=1; i<=m; i++){
        int tip_operatie, ind1,ind2;
        fin >> tip_operatie >> ind1 >> ind2;
        if(tip_operatie) update(1,1,n,ind1,ind2);
        else fout << query(1,1,n,ind1,ind2) << '\n';
    }
    return 0;
}