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seg_tree.cpp
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seg_tree.cpp
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//Ram Ram
#include <bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ll long long
#define int long long int
#define _test int _TEST; cin>>_TEST; while(_TEST--)
#define ff first
#define ss second
#define pb push_back
#define ppb pop_back
#define all(x) (x).begin(),(x).end()
#define fr(i,s,e) for(int i=s;i<e;i++)
#define read(x) for(auto &i:x) cin>>i;
#define write(x) for(auto i:x) cout<<i<<" ";
#define input(n) int n; cin>>n;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update>pbds;//find_by_order,order_of_key
const int N=2e5+10;
int a[N],seg[4*N];
void build(int ind,int tl,int tr){
if(tl==tr){
seg[ind]=a[tl];
return;
}
int mid=(tl+tr)/2;
build(2*ind+1,tl,mid);
build(2*ind+2,mid+1,tr);
seg[ind]=min(seg[2*ind+1],seg[2*ind+2]);
}
int query(int ind,int tl,int tr,int l,int r){
if(tl>=l && tr<=r) return seg[ind];
if(l>tr || r<tl) return INT_MAX;
int mid=(tl+tr)/2;
return min(query(2*ind+1,tl,mid,l,r),query(2*ind+2,mid+1,tr,l,r));
}
void pointUpdate(int ind,int tl,int tr,int node,int val){
if(tl==tr){
seg[ind]=val;
return;
}
int mid=(tl+tr)/2;
if(node<=mid && node>=tl) pointUpdate(2*ind+1,tl,mid,node,val);
else pointUpdate(2*ind+2,mid+1,tr,node,val);
seg[ind]=min(seg[2*ind+1],seg[2*ind+2]);
}
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
//Segment tree is a data structure which is capable of performing range queries in O(logn) time
//and also perfrom updates in O(logn) time so it is quite useful.
// we will use devide and conqure approach.
int n,q;
cin>>n>>q;
for(int i=0;i<n;i++) cin>>a[i];
build(0,0,n-1);
while(q--){
int t,l,r;
cin>>t>>l>>r;
if(t==1){
l--;
pointUpdate(0,0,n-1,l,r);
}
else{
l--;
r--;
cout<<query(0,0,n-1,l,r)<<"\n";
}
}
}