[hiho1586]Minimum

题意：区间内乘积最小值，带修改。
解题关键：线段树裸题，考场上以为x y必须不等，还维护了次小值，尼玛嗨尼玛嗨，划水一整场，心态爆炸。

注意坐标需要+1

 #include<cstdio>
 #include<cstring>
 #include<cstdlib>
 #include<algorithm>
 #include<cmath>
 #include<iostream>
 #define inf 0x3f3f3f3f
 using namespace std;
 typedef long long ll;
 const int maxn=;
 ll a[maxn],tree1[maxn<<],tree2[maxn<<];
 void pushup(int rt){
     tree1[rt]=max(tree1[rt<<|],tree1[rt<<]);
     tree2[rt]=min(tree2[rt<<|],tree2[rt<<]);
 }
 void build(ll rt,ll l,ll r){
     if(l==r){
         tree1[rt]=tree2[rt]=a[l];
         return;
     }
     ll mid=(l+r)>>;
     build(rt<<,l,mid);
     build(rt<<|,mid+,r);
     pushup(rt);
 }

 void update(ll rt,ll l,ll r,ll p,ll c){
     if(l>r) return;
     if(l==r){
         tree1[rt]=tree2[rt]=c;
         return;
     }
     ll mid=(l+r)>>;
     if(p<=mid) update(rt<<, l, mid, p, c);
     else update(rt<<|, mid+, r, p, c);
     pushup(rt);
 }

 ll query1(ll rt,ll l,ll r,ll tl,ll tr){
     if(tl>tr) return -inf;
     if(tl<=l&&tr>=r){
         return tree1[rt];
     }
     ll mid=(l+r)>>,res=-inf;
     if(tl<=mid) res=max(res,query1(rt<<,l,mid,tl,tr));
     if(tr>mid) res=max(query1(rt<<|,mid+,r,tl,tr),res);
     return res;
 }

 ll query2(ll rt,ll l,ll r,ll tl,ll tr){
     if(tl>tr) return inf;
     if(tl<=l&&tr>=r){
         return tree2[rt];
     }
     ll mid=(l+r)>>,res=inf;
     if(tl<=mid) res=min(res,query2(rt<<,l,mid,tl,tr));
     if(tr>mid) res=min(query2(rt<<|,mid+,r,tl,tr),res);
     return res;
 }

 int main(){
     ll n,m;
     ios::sync_with_stdio();
     cin.tie();
     cout.tie();
     ll t;
     cin>>t;
     while(t--){
         cin>>n;
         n=<<n;
         memset(tree1, , sizeof tree1);
         memset(tree2,,sizeof tree2);
         memset(a,,sizeof a);
         for(int i=;i<=n;i++) cin>>a[i];
         build(, , n);
         cin>>m;
         for(int i=;i<m;i++){
             int a,b,c;
             cin>>a>>b>>c;
             if(a==){
                 ll ans1=query1(,,n,b+,c+);
                 ll ans2=query2(,,n,b+,c+);
                 if(ans1>=&&ans2<){
                     cout<<1ll*ans1*ans2<<"\n";
                     continue;
                 }
                 else if(ans1>=&&ans2>=){
                     cout<<1ll*ans2*ans2<<"\n";
                     continue;
                 }
                 else{
                     cout<<1ll*ans1*ans1<<"\n";
                 }
             }
             else{
                 update(, , n, b+, c);
             }
         }
     }

 }