Cod sursa(job #1880861)

Utilizator roxannemafteiuMafteiu-Scai Roxana roxannemafteiu Data 15 februarie 2017 22:45:36
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.57 kb
#include <bits/stdc++.h>

using namespace std;

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

const int N_MAX = 1e5;
const int INF = 11111111;

int n, m;
int v[N_MAX + 5], st[4 * N_MAX + 5];

void build(int node, int l, int r) {
    if (l == r) {
        st[node] = v[l];
        return;
    }

    int m = (l + r) / 2;
    int ls = node * 2, lr = ls + 1;

    build(ls, l, m);
    build(lr, m + 1, r);

    st[node] = max(st[ls], st[lr]);
}

void update(int node, int l, int r, int pos, int val) {
    if (l == r) {
        st[node] = val;
        return;
    }

    int m = (l + r) / 2;
    int ls = 2 * node, lr = ls + 1;

    if (pos <= m) {
        update(ls, l, m, pos, val);
    } else {
        update(lr, m + 1, r, pos, val);
    }

    st[node] = max(st[ls], st[lr]);
}

int query(int node, int l, int r, int ql, int qr) {
    if (ql <= l && r <= qr) {
        return st[node];
    }

    int m = (l + r) / 2;
    int ls = 2 * node, lr = ls + 1;

    int ans = -INF;
    if (ql <= m) {
        ans = max(ans, query(ls, l, m, ql, qr));
    }
    if (m < qr) {
        ans = max(ans, query(lr, m + 1, r, ql, qr));
    }

    return ans;
}


int main() {
    fin >> n >> m;
    for (int i = 1; i <= n; ++i) {
        fin >> v[i];
    }

    build(1, 1, n);

    for (int i = 0; i < m; ++i) {
        int x, y, z;
        fin >> x >> y >> z;
        if (x == 1) {
            update(1, 1, n, y, z);

        } else {
            fout << query(1, 1, n, y, z) << '\n';
        }
    }

    return 0;
}