Cod sursa(job #2073925)

Utilizator mihai.alphamihai craciun mihai.alpha Data 23 noiembrie 2017 20:48:50
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.26 kb
#include <bits/stdc++.h>

using namespace std;

const int maxn = 1e5 + 5;

int N, M;
int arb[maxn * 4];

void update(int nod, int st, int dr, int val, int poz)  {
    if(st > poz || dr < poz)
        return;
    if(st == dr)  {
        arb[nod] = val;
        return;
    }
    update(nod * 2, st, (st + dr) / 2, val, poz),
    update(nod * 2 + 1, (st + dr) / 2 + 1, dr, val, poz);
    arb[nod] = max(arb[nod * 2], arb[nod * 2 + 1]);
    return;
}

int a, b, ans;

void query(int nod, int st, int dr)  {
    if(st >= a && dr <= b)  {
        ans = max(ans, arb[nod]);
        return;
    }
    int mid = (st + dr) / 2;
    if(mid >= a)
        query(nod * 2, st, mid);
    if(mid < b)
        query(nod * 2 + 1, mid + 1, dr);
}

int main()  {
    freopen("arbint.in", "r", stdin);
    freopen("arbint.out", "w", stdout);
    scanf("%d%d", &N, &M);
    for(int i = 1;i <= N;i++)  {
        int x;
        scanf("%d", &x);
        update(1, 1, N, x, i);
    }
    while(M--)  {
        int op;
        scanf("%d%d%d", &op, &a, &b);
        if(op == 0)  {
            ans = 0;
            query(1, 1, N);
            cout << ans << "\n";
        }
        else  {
            update(1, 1, N, b, a);
        }
    }
    return 0;
}