Cod sursa(job #2908999)

Utilizator ioana.cCaprariu Ioana ioana.c Data 7 iunie 2022 18:40:05
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.26 kb
#include <fstream>

using namespace std;

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

int n, m, A[100001], ma[400001], i, a, b, c;

void query(int x, int st, int dr){
    if(st == dr)
        ma[x] = A[st];
    else{
        int mij = (st+dr)/2;
        query(x*2, st, mij);
        query(x*2+1, mij+1, dr);
        ma[x] = max(ma[x*2], ma[x*2+1]);
    }
}

int maxi(int x, int st, int dr, int l, int r){
    if(l > r)
        return 0;
    if(l==st && r==dr)
        return ma[x];
    int mij = (st + dr) / 2;
    return max(maxi(x*2, st, mij, l, min(r,mij)), maxi(x*2+1, mij+1, dr, max(l,mij+1), r));
}

void update(int x, int st, int dr, int pos, int new_val){
    if(st == dr)
        ma[x] = new_val;
    else{
        int mij = (st + dr) / 2;
        if(pos <= mij)
            update(x*2, st, mij, pos, new_val);
        else
            update(x*2+1, mij+1, dr, pos, new_val);
        ma[x] = max(ma[x*2], ma[x*2+1]);
    }
}

int main(){
    fin >> n >> m;
    for(i=1; i<=n; i++)
        fin >> A[i];
    query(1, 1, n);
    for(i=1; i<=m; i++){
        fin >> c >> a >> b;
        if(c == 0)
            fout << maxi(1, 1, n, a, b) << '\n';
        else
            update(1, 1, n, a, b);
    }
    return 0;
}