[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

  1 #include<cstdio>
  2 #include<cstring>
  3 #include<cstdlib>
  4 #include<algorithm>
  5 #include<cmath>
  6 #include<iostream>
  7 #define inf 0x3f3f3f3f
  8 using namespace std;
  9 typedef long long ll;
 10 const int maxn=131073;
 11 ll a[maxn],tree1[maxn<<2],tree2[maxn<<2];
 12 void pushup(int rt){
 13     tree1[rt]=max(tree1[rt<<1|1],tree1[rt<<1]);
 14     tree2[rt]=min(tree2[rt<<1|1],tree2[rt<<1]);
 15 }
 16 void build(ll rt,ll l,ll r){
 17     if(l==r){
 18         tree1[rt]=tree2[rt]=a[l];
 19         return;
 20     }
 21     ll mid=(l+r)>>1;
 22     build(rt<<1,l,mid);
 23     build(rt<<1|1,mid+1,r);
 24     pushup(rt);
 25 }
 26
 27 void update(ll rt,ll l,ll r,ll p,ll c){
 28     if(l>r) return;
 29     if(l==r){
 30         tree1[rt]=tree2[rt]=c;
 31         return;
 32     }
 33     ll mid=(l+r)>>1;
 34     if(p<=mid) update(rt<<1, l, mid, p, c);
 35     else update(rt<<1|1, mid+1, r, p, c);
 36     pushup(rt);
 37 }
 38
 39 ll query1(ll rt,ll l,ll r,ll tl,ll tr){
 40     if(tl>tr) return -inf;
 41     if(tl<=l&&tr>=r){
 42         return tree1[rt];
 43     }
 44     ll mid=(l+r)>>1,res=-inf;
 45     if(tl<=mid) res=max(res,query1(rt<<1,l,mid,tl,tr));
 46     if(tr>mid) res=max(query1(rt<<1|1,mid+1,r,tl,tr),res);
 47     return res;
 48 }
 49
 50 ll query2(ll rt,ll l,ll r,ll tl,ll tr){
 51     if(tl>tr) return inf;
 52     if(tl<=l&&tr>=r){
 53         return tree2[rt];
 54     }
 55     ll mid=(l+r)>>1,res=inf;
 56     if(tl<=mid) res=min(res,query2(rt<<1,l,mid,tl,tr));
 57     if(tr>mid) res=min(query2(rt<<1|1,mid+1,r,tl,tr),res);
 58     return res;
 59 }
 60
 61 int main(){
 62     ll n,m;
 63     ios::sync_with_stdio(0);
 64     cin.tie(0);
 65     cout.tie(0);
 66     ll t;
 67     cin>>t;
 68     while(t--){
 69         cin>>n;
 70         n=1<<n;
 71         memset(tree1, 0, sizeof tree1);
 72         memset(tree2,0,sizeof tree2);
 73         memset(a,0,sizeof a);
 74         for(int i=1;i<=n;i++) cin>>a[i];
 75         build(1, 1, n);
 76         cin>>m;
 77         for(int i=0;i<m;i++){
 78             int a,b,c;
 79             cin>>a>>b>>c;
 80             if(a==1){
 81                 ll ans1=query1(1,1,n,b+1,c+1);
 82                 ll ans2=query2(1,1,n,b+1,c+1);
 83                 if(ans1>=0&&ans2<0){
 84                     cout<<1ll*ans1*ans2<<"\n";
 85                     continue;
 86                 }
 87                 else if(ans1>=0&&ans2>=0){
 88                     cout<<1ll*ans2*ans2<<"\n";
 89                     continue;
 90                 }
 91                 else{
 92                     cout<<1ll*ans1*ans1<<"\n";
 93                 }
 94             }
 95             else{
 96                 update(1, 1, n, b+1, c);
 97             }
 98         }
 99     }
100
101 }