Cod sursa(job #2293915)

Utilizator MihneaGhiraMihnea MihneaGhira Data 1 decembrie 2018 18:24:00
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.27 kb
#include<fstream>
using namespace std;
ifstream fin("arbint.in");
ofstream fout("arbint.out");
int op,i,m,n,p,x,maxim;
int a[400005],v[400005];

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]);
    }
    return;
}

void qr(int nod,int st,int dr,int A,int B){
    if(A<=st&&dr<=B){
        maxim=max(maxim,a[nod]);
    }else{
        int mid=(st+dr)/2;
        if(A<=mid)
            qr(2*nod,st,mid,A,B);
        if(B>mid)
            qr(2*nod+1,mid+1,dr,A,B);
    }
}

void upd(int nod,int st,int dr,int p,int x){
    if(st==dr){
        a[nod]=x;
    }else{
        int mid=(st+dr)/2;
        if(p<=mid)
            upd(2*nod,st,mid,p,x);
        if(p>mid)
            upd(2*nod+1,mid+1,dr,p,x);
        a[nod]=max(a[2*nod],a[2*nod+1]);
    }
}


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>>p>>x;
        if(op==1){
            upd(1,1,n,p,x);
        }else{
            maxim=-10000000;
            qr(1,1,n,p,x);
            fout<<maxim<<"\n";
        }
    }
    return 0;

}