Cod sursa(job #1969892)

Utilizator tudormaximTudor Maxim tudormaxim Data 18 aprilie 2017 18:28:02
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.27 kb
#include <iostream>
#include <fstream>
using namespace std;

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

const int maxn = 1e5 + 5;
int T[maxn << 2];
int n, q, maxx;

void Update(int node, int st, int dr, int pos, int val) {
    if (st == dr) {
        T[node] = val;
        return;
    }
    int mid = (st + dr) >> 1;
    if (pos <= mid) Update(node << 1, st, mid, pos, val);
    if (pos >  mid) Update(node << 1 | 1, mid + 1, dr, pos, val);
    T[node] = max(T[node << 1], T[node << 1 | 1]);
}

void Query(int node, int st, int dr, int inc, int sf) {
    if (inc <= st && dr <= sf) {
        maxx = max(maxx, T[node]);
        return;
    }
    int mid = (st + dr) >> 1;
    if (inc <= mid) Query(node << 1, st, mid, inc, sf);
    if (sf > mid) Query(node << 1 | 1, mid + 1, dr, inc, sf);
}

int main() {
    ios_base :: sync_with_stdio(false);
    fin >> n >> q;
    for (int i = 1; i <= n; i++) {
        int x;
        fin >> x;
        Update(1, 1, n, i, x);
    }
    while (q--) {
        int op, x, y;
        fin >> op >> x >> y;
        if (op == 1) {
            Update(1, 1, n, x, y);
        } else {
            maxx = 0;
            Query(1, 1, n, x, y);
            fout << maxx << "\n";
        }
    }
    return 0;
}