Cod sursa(job #2082654)

Utilizator stoianmihailStoian Mihail stoianmihail Data 6 decembrie 2017 17:35:02
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.12 kb
#include <stdio.h>

#define MAX_N 100000

int N, Q;
int tree[MAX_N * 2 + 1];

int MAX(int X, int Y) {
  return X > Y ? X : Y;
}

void update(int x, int val) {
  x += N;
  tree[x] = val;
  while (x > 1) {
    tree[x >> 1] = MAX(tree[x], tree[x ^ 1]);
    x >>= 1;
  }
}

int query(int a, int b) {
  int ans = 0;
  a += N;
  b += N;
  while (a < b) {
    if (a & 1) {
      ans = MAX(ans, tree[a++]);
    }
    if (b & 1) {
      ans = MAX(ans, tree[--b]);
    }
    a >>= 1;
    b >>= 1;
  }
  return ans;
}

int main(void) {
  FILE *f = fopen("arbint.in", "r");

  int i;
  fscanf(f, "%d %d", &N, &Q);
  for (i = 1; i <= N; i++) {
    fscanf(f, "%d", &tree[i + N]);
  }
  for (i = N; i >= 1; i--) {
    tree[i] = MAX(tree[i << 1], tree[(i << 1) | 1]);
  }

  int task, a, b;
  freopen("arbint.out", "w", stdout);
  while (Q) {
    fscanf(f, "%d %d %d", &task, &a, &b);
    if (task == 0) {
      fprintf(stdout, "%d\n", query(a, b + 1));
    } else {
      update(a, b);
    }
    Q--;
  }
  freopen("chimic.out", "w", stdout);
  fprintf(stdout, "%lld\n", tree[1]);
  return 0;
}