Cod sursa(job #2180949)

Utilizator TooHappyMarchitan Teodor TooHappy Data 21 martie 2018 12:25:14
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.7 kb
#include <bits/stdc++.h>
using namespace std;
     
ifstream in("arbint.in");
ofstream out("arbint.out");
 
const int minInf = -1e9;
 
int a[100005], aInt[4 * 100005];
 
void build(int currentNode, int l, int r) {
    if(l == r) {
        aInt[currentNode] = a[l];
        return;
    }
     
    int mid = (l + r) / 2;
 
    build(2 * currentNode + 1, l, mid);
    build(2 * currentNode + 2, mid + 1 ,r);
    aInt[currentNode] = max(aInt[2 * currentNode + 1], aInt[2 * currentNode + 2]);
}
 
int query(int currentNode, int l, int r, int a, int b) {
    if(a <= l && b >= r) {
        return aInt[currentNode];
    }
 
    int mid = (l + r) / 2;
 
    if(a > r || b < l) {
        return minInf;
    }
 
    return max(query(2 * currentNode + 1, l, mid, a, b), query(2 * currentNode + 2, mid + 1, r, a, b));
}
 
void update(int currentNode, int l, int r, int targetPoz, int newVal) {
    if(l == r) {
        aInt[currentNode] = newVal;
        return;
    }
 
    int mid = (l + r) / 2;
 
    if(targetPoz <= mid) {
        update(2 * currentNode + 1, l, mid, targetPoz, newVal);
    } else {
        update(2 * currentNode + 2, mid + 1, r, targetPoz, newVal);
    }
 
    aInt[currentNode] = max(aInt[2 * currentNode + 1], aInt[2 * currentNode + 2]);
}
 
int main() {
    ios::sync_with_stdio(false); in.tie(0); out.tie(0);
   
    int n, m; in >> n >> m;
 
    for(int i = 0; i < n; ++i) {
        in >> a[i];
    }
 
    build(0,0, n - 1);
 
    for(int i = 1; i <= m; ++i) {
        int x, a, b; in >> x >> a >> b;
 
        if(x == 0) {
            out << query(0, 0, n - 1, a - 1, b - 1) << '\n';
        } else {
            update(0, 0, n - 1, a - 1, b);
        }
    }
      
    in.close(); out.close();
     
    return 0;
}