Cod sursa(job #2818650)

Utilizator biancalautaruBianca Lautaru biancalautaru Data 16 decembrie 2021 16:51:20
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.28 kb
#include <fstream>
using namespace std;
ifstream fin("arbint.in");
ofstream fout("arbint.out");
int n,m,i,op,x,y,v[100001],a[400001];

void build(int nod,int st,int dr) {
    if (st==dr)
        a[nod]=v[st];
    else {
        int mid=(st+dr)/2;
        build(2*nod,st,mid);
        build(2*nod+1,mid+1,dr);
        a[nod]=max(a[2*nod],a[2*nod+1]);
    }
}

void update(int nod,int st,int dr,int poz,int val) {
    if (st==dr)
        a[nod]=val;
    else {
        int mid=(st+dr)/2;
        if (poz<=mid)
            update(2*nod,st,mid,poz,val);
        else
            update(2*nod+1,mid+1,dr,poz,val);
        a[nod]=max(a[2*nod],a[2*nod+1]);
    }
}

int query(int nod,int st,int dr,int qst,int qdr) {
    if (qst<=st && dr<=qdr)
        return a[nod];
    int mid=(st+dr)/2;
    if (qdr<=mid)
        return query(2*nod,st,mid,qst,qdr);
    if (mid+1<=qst)
        return query(2*nod+1,mid+1,dr,qst,qdr);
    return max(query(2*nod,st,mid,qst,qdr),query(2*nod+1,mid+1,dr,qst,qdr));
}

int main() {
    fin>>n>>m;
    for (i=1;i<=n;i++)
        fin>>v[i];
    build(1,1,n);
    for (i=1;i<=m;i++) {
        fin>>op>>x>>y;
        if (op==0)
            fout<<query(1,1,n,x,y)<<"\n";
        else
            update(1,1,n,x,y);
    }
    return 0;
}