Language: C++

            #include <bits/stdc++.h>
            #include<iostream>
            #include<cstdio>
            #include<vector>
            #include<queue>
            #include<map>
            #include<cstring>
            #include<string>
            #include <math.h>
            #include<algorithm>
        //    #include <boost/multiprecision/cpp_int.hpp>
            #include<functional>
          #define int long long
            #define inf  1000000007
            #define pa pair<int,int>
    #define ll long long
            #define pal pair<ll,ll>
            #define ppa pair<int,pa>
            #define  mp make_pair
            #define EPS (1e-10)
            #define equals(a,b) (fabs((a)-(b))<EPS)
     
            using namespace std;
     
            class Point{
            	public:
            	double x,y;
            	Point(double x=0,double y=0):x(x),y(y) {}
            	Point operator + (Point p) {return Point(x+p.x,y+p.y);}
            	Point operator - (Point p) {return Point(x-p.x,y-p.y);}
            	Point operator * (double a) {return Point(x*a,y*a);}
            	Point operator / (double a) {return Point(x/a,y/a);}
            	double absv() {return sqrt(norm());}
            	double norm() {return x*x+y*y;}
            	bool operator < (const Point &p) const{
            		return x != p.x ? x<p.x: y<p.y;
            	}
            	bool operator == (const Point &p) const{
            		return fabs(x-p.x)<EPS && fabs(y-p.y)<EPS;
            	}
            };
            typedef Point Vector;
     
            struct Segment{
            Point p1,p2;
            };
     
        double hen(Vector a){
        if(fabs(a.x)<EPS && a.y>0) return acos(0);
        else if(fabs(a.x)<EPS && a.y<0) return 3*acos(0);
        else if(fabs(a.y)<EPS && a.x<0) return 2*acos(0);
        else if(fabs(a.y)<EPS && a.x>0) return 0.0;
        else if(a.y>0) return acos(a.x/a.absv());
        else return 2*acos(0)+acos(-a.x/a.absv());
     
        }
     
            double dot(Vector a,Vector b){
            	return a.x*b.x+a.y*b.y;
            }
            double cross(Vector a,Vector b){
            	return a.x*b.y-a.y*b.x;
            }
        
            //----------------kokomade temple------------
int n,m,k,x,t;

int N=262144;

int q[100002]={0};
int qq[100002]={0};
pa sgt[530000];

pa minis(int i,int j ){
if(i==j) return sgt[i];
	else if(i%2==1){
		pa z=minis(i+1,j);
		if(sgt[i].first>z.first)return sgt[i] ;
		else return z;
	}
		else if(j%2==0) 	{
		pa z=minis(i,j-1);
		if(sgt[j].first>z.first)return sgt[j] ;
		else return z;
	}
else return minis(i/2,j/2);
}

pa sgtmin(int i ,int j) {
	return minis(i+N,j+N);
}

void upd(int x,int y){
	x+=N;
sgt[x].first=y;
	sgt[x].second=x;
x=x/2;
while(x != 0){
	if(sgt[2*x+1].first>sgt[2*x].first){
		sgt[x]=sgt[2*x+1];
	}
	else sgt[x]=sgt[2*x];

x=x/2;
}
}



    signed main(){

    	cin>>n>>t;
    	for(int i=N;i<2*N;i++) sgt[i]=make_pair(0,i-N);
    	
    	for(int i=N;i<N+n;i++){
    		cin>>x;
    		use[x]=1;
    		sgt[i].first=x;
    	}
    	for(int i=N-1;i>0;i--){
		if(sgt[2*i].first<sgt[2*i+1].first) sgt[i]=sgt[2*i+1];
		else sgt[i]=sgt[2*i];
	}
    	
    	int ma=0;
    	vector<pa> ve;
    	
    	for(int i=0;i<n;i++){
    		 m=sgtmin(i+1,N-1).first;
    		m -= sgt[N+i].first;
    		int z=sgtmin(i+1,N-1).second;
    	
    		if(m>ma){
    			ve.clear();
    			ve.push_back(mp(i,z));
    		}
    		else if(m==ma){
    			ve.push_back(mp(i,z));
    		}
    		
    		ma=max(ma,m);
    		
    		
    	
    	}
    	for(int i=0;i<ve.size();i++){
    //		cout<<ve[i].first<<" "<<ve[i].second<<endl;
    		ve[i].first++;
    		ve[i].second++;
    //		cout<<ve[i].first<<" "<<ve[i].second<<endl;
    		q[ve[i].first]=ve[i].second;
    		qq[ve[i].second]=ve[i].first;
    	}
  //  	for(int i=0;i<10;i++) cout<<" "<<q[i]<<" "<<qq[i]<<endl;
    	int ans=0;
    	for(int i=0;i<100002;i++){
    		int num;
    		if(q[i]!=0 && qq[i]==0){
    			int e=i;
    			num=0;
    			while(num<3){
    	//			cout<<e<<endl;
    				e=q[e];
    		//		cout<<e<<endl;
    				num++;
    	//			cout<<"qe= "<<q[e]<<endl; 
    				if(q[e]==0) break;
    			}
    			
    			ans += num*(num+1)/2;
    		}
    	//	ans += num*(num+1)/2;
    		
    	}
    	
    	
    	cout<<ans<<endl;
    //	printf("%.10f\n",ans);
    	return 0;
    }

Compiler output:
a.cc: In function 'int main()':
a.cc:117:17: error: 'use' was not declared in this scope
  117 |                 use[x]=1;
      |                 ^~~