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SEGMENTTREE.cpp
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SEGMENTTREE.cpp
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#include <bits/stdc++.h>
using namespace std;
#define ll int64_t
#define pii pair<ll, ll>
#define pb push_back
class segtree {
public:
ll n;
ll size;
vector<ll> arr;
vector<ll> tree;
ll ceillog(ll x) {
ll count = 0;
ll p = 1;
while (p * 2 <= x) {
p *= 2;
count++;
}
if (p == x) return p;
return p * 2;
}
ll combine(ll a, ll b) { // example combine function (must satisfy commutative + associative + identity)
if (a < b) return a;
return b;
}
segtree(vector<ll>& ray) {
n = ray.size();
size = ceillog(n);
for (ll i = 0; i < size; i++) arr.pb(0);
for (ll i = 0; i < 2 * size; i++) tree.pb(0);
for (ll i = 0; i < n; i++) update(i, ray[i]);
}
ll query(ll a, ll b) {
a += size;
b += size;
ll res = LLONG_MAX; // initial value
while (a <= b) {
if (a % 2 == 1) res = combine(res, tree[a++]);
if (b % 2 == 0) res = combine(res, tree[b--]);
a /= 2;
b /= 2;
}
return res;
}
ll change(ll i, ll x) {
arr[i] += x;
i += size;
tree[i] += x;
for (int k = i / 2; k >= 1; k /= 2) tree[k] = combine(tree[2 * k], tree[2 * k + 1]);
return x;
}
ll update(ll i, ll x) {
ll prev = arr[i];
change(i, x - prev);
return x;
}
void print() {
cout << "[" << arr[0];
for (ll i = 1; i < size; i++) cout << " " << arr[i];
cout << "] = ";
cout << "[" << tree[0];
for (ll i = 1; i < 2 * size; i++) cout << " " << tree[i];
cout << "]";
}
void println() {
print();
cout << endl;
}
};
int main() // https://cses.fi/problemset/task/1649/
{
ll n, q;
cin >> n >> q;
vector<ll> arr(n, 0);
for (ll i = 0; i < n; i++) cin >> arr[i];
segtree tree(arr);
// tree.println();
ll c, a, b;
for (ll i = 0; i < q; i++) {
cin >> c >> a >> b;
if (c == 1) {
tree.update(a - 1, b);
// tree.println();
}
else cout << tree.query(a - 1, b - 1) << endl;
}
return 0;
}