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// Algo : Wavelet Tree

struct wavelet_tree{
	#define vi vector<int>
	#define pb push_back

	int lo, hi;
	wavelet_tree *l, *r;
	vi b;

	//nos are in range [x,y]
	//array indices are [from, to)
	wavelet_tree(int *from, int *to, int x, int y){
		lo = x, hi = y;
		if(lo == hi or from >= to) return;
		int mid = (lo+hi)/2;
		auto f = [mid](int x){
			return x <= mid;
		};
		b.reserve(to-from+1);
		b.pb(0);
		for(auto it = from; it != to; it++)
			b.pb(b.back() + f(*it));
		//see how lambda function is used here
		auto pivot = stable_partition(from, to, f);
		l = new wavelet_tree(from, pivot, lo, mid);
		r = new wavelet_tree(pivot, to, mid+1, hi);
	}

	//kth smallest element in [l, r]
	int kth(int l, int r, int k){
		if(l > r) return 0;
		if(lo == hi) return lo;
		int inLeft = b[r] - b[l-1];
		int lb = b[l-1]; //amt of nos in first (l-1) nos that go in left
		int rb = b[r]; //amt of nos in first (r) nos that go in left
		if(k <= inLeft) return this->l->kth(lb+1, rb , k);
		return this->r->kth(l-lb, r-rb, k-inLeft);
	}

	//count of nos in [l, r] Less than or equal to k
	int LTE(int l, int r, int k) {
		if(l > r or k < lo) return 0;
		if(hi <= k) return r - l + 1;
		int lb = b[l-1], rb = b[r];
		return this->l->LTE(lb+1, rb, k) + this->r->LTE(l-lb, r-rb, k);
	}

	//count of nos in [l, r] equal to k
	int count(int l, int r, int k) {
		if(l > r or k < lo or k > hi) return 0;
		if(lo == hi) return r - l + 1;
		int lb = b[l-1], rb = b[r], mid = (lo+hi)/2;
		if(k <= mid) return this->l->count(lb+1, rb, k);
		return this->r->count(l-lb, r-rb, k);
	}
	~wavelet_tree(){
		delete l;
		delete r;
	}
};

// Call :
wavelet_tree *T;
T = new wavelet_tree(arr+1, arr+N+1, 1, MAXN);