Sunset

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;

const int MX = 200010;
const int MOD = 1e9+7;
const int inf = 2e9;
const ll linf = 2e18;

int n, q;
int H[MX], lft[MX];

struct _st{ int l, r, idx, ans; } query[MX];

int tree[MX];
void upt(int x, int d){
	for(; 0<x && x<=n; x+=x&(-x)) tree[x]+=d;
}
int sum(int x){
	int ans=0;
	for(; 0<x; x-=x&(-x)) ans+=tree[x];
	return ans;
}


int main(){
	ios::sync_with_stdio(0), cin.tie(0);
	cin>>n>>q;
	for(int i=1; i<=n; i++) cin>>H[i];
	for(int i=1; i<=q; i++){
		int l,r; cin>>l>>r;
		query[i] = {l,r,i};
	}

	stack<int> stk;
	for(int i=n; i>=1; i--){
		while(!stk.empty()){
			int j = stk.top();
			if(H[i]>=H[j]) lft[j]=i, stk.pop();
			else break;
		}
		stk.push(i);
	}
	while(!stk.empty()){
		int j = stk.top(); stk.pop();
		lft[j]=0;
	}

	int frt=0, bck=0;
	pii V[MX];
	for(int i=1; i<=n; i++) V[bck++] = {lft[i], i};
	sort(V, V+bck);

	sort(query+1, query+q+1, [](_st &a, _st &b){ return a.l<b.l; });

	for(int i=1; i<=q; i++){
		int l=query[i].l, r=query[i].r;
		while(frt<bck){
			int x,j; tie(x,j) = V[frt];
			if(x>=l) break;
			upt(j,1); frt++;
		}
		query[i].ans = sum(r) - sum(l-1);
	}

	sort(query+1, query+q+1, [](_st &a, _st &b){ return a.idx < b.idx; });

	for(int i=1; i<=q; i++) cout<<query[i].ans<<'\n';

	return 0;
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 1

Verdict: ACCEPTED

Test 7

Group: 1

Verdict: ACCEPTED

Test 8

Group: 1

Verdict: ACCEPTED

Test 9

Group: 1

Verdict: ACCEPTED

Test 10

Group: 1

Verdict: ACCEPTED

Test 11

Group: 1

Verdict: ACCEPTED

Test 12

Group: 1

Verdict: ACCEPTED

Test 13

Group: 1

Verdict: ACCEPTED

Test 14

Group: 1

Verdict: ACCEPTED

Test 15

Group: 1

Verdict: ACCEPTED

Test 16

Group: 1

Verdict: ACCEPTED

Test 17

Group: 1

Verdict: ACCEPTED

Test 18

Group: 2

Verdict: ACCEPTED

Test 19

Group: 2

Verdict: ACCEPTED

Test 20

Group: 2

Verdict: ACCEPTED

Test 21

Group: 2

Verdict: ACCEPTED

Test 22

Group: 2

Verdict: ACCEPTED

Test 23

Group: 2

Verdict: ACCEPTED

Test 24

Group: 2

Verdict: ACCEPTED

Test 25

Group: 2

Verdict: ACCEPTED

Test 26

Group: 2

Verdict: ACCEPTED

Test 27

Group: 2

Verdict: ACCEPTED

Test 28

Group: 2

Verdict: ACCEPTED

Test 29

Group: 2

Verdict: ACCEPTED

Test 30

Group: 2

Verdict: ACCEPTED

Test 31

Group: 2

Verdict: ACCEPTED

Test 32

Group: 3

Verdict: ACCEPTED

Test 33

Group: 3

Verdict: ACCEPTED

Test 34

Group: 3

Verdict: ACCEPTED

Test 35

Group: 3

Verdict: ACCEPTED

Test 36

Group: 3

Verdict: ACCEPTED

Test 37

Group: 3

Verdict: ACCEPTED

Test 38

Group: 3

Verdict: ACCEPTED

Test 39

Group: 3

Verdict: ACCEPTED

Test 40

Group: 3

Verdict: ACCEPTED

Test 41

Group: 3

Verdict: ACCEPTED

Test 42

Group: 3

Verdict: ACCEPTED

Test 43

Group: 3

Verdict: ACCEPTED

Test 44

Group: 3

Verdict: ACCEPTED

Test 45

Group: 3

Verdict: ACCEPTED

Test 46

Group: 3

Verdict: ACCEPTED

Test 47

Group: 3

Verdict: ACCEPTED

Test 48

Group: 3

Verdict: ACCEPTED

Test 49

Group: 3

Verdict: ACCEPTED

Test 50

Group: 3

Verdict: ACCEPTED

Test 51

Group: 3

Verdict: ACCEPTED

Test 52

Group: 3

Verdict: ACCEPTED

Test 53

Group: 3

Verdict: ACCEPTED

Test 54

Group: 3

Verdict: ACCEPTED