Competitive_Programming/Structures/SegTree.cpp at master · jonh14lk/Competitive_Programming · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
#include <bits/stdc++.h>
using namespace std;

#define PI acos(-1)
#define pb push_back
#define int long long int
#define mp make_pair
#define pi pair<int, int>
#define pii pair<pi, int>
#define fir first
#define sec second
#define MAXN 100001
#define MAXL 100
#define mod 1000000007

vector<int> seg;
vector<int> v;

int single(int x)
{
  return x;
}
int neutral()
{
  return 0;
}
int merge(int a, int b)
{
  return a + b;
}
void update(int i, int l, int r, int q, int x)
{
  if (l == r)
  {
    seg[i] = single(x);
    return;
  }
  int mid = (l + r) >> 1;
  if (q <= mid)
    update(i << 1, l, mid, q, x);
  else
    update((i << 1) | 1, mid + 1, r, q, x);
  seg[i] = merge(seg[i << 1], seg[(i << 1) | 1]);
}
int query(int l, int r, int ql, int qr, int i)
{
  int mid = (l + r) >> 1;
  if (l > r || l > qr || r < ql)
    return neutral();
  if (l >= ql && r <= qr)
    return seg[i];
  return merge(query(l, mid, ql, qr, i << 1), query(mid + 1, r, ql, qr, (i << 1) | 1));
}
void build(int l, int r, int i)
{
  if (l == r)
  {
    seg[i] = single(v[l]);
    return;
  }
  int mid = (l + r) >> 1;
  build(l, mid, i << 1);
  build(mid + 1, r, (i << 1) | 1);
  seg[i] = merge(seg[i << 1], seg[(i << 1) | 1]);
}
signed main()
{
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n, q;
  cin >> n >> q;
  v.resize(n);
  seg.resize(4 * n);
  for (int i = 0; i < n; i++)
    cin >> v[i];
  build(0, n - 1, 1);
  while (q--)
  {
    int l, r;
    int t;
    cin >> t >> l >> r;
    if (t == 2)
      cout << query(0, n - 1, l, r - 1, 1) << endl;
    else
      update(1, 0, n - 1, l, r);
  }
}