Point in Polygon

#include <bits/stdc++.h>
using namespace std;
 
struct Point {
    long long x;
    long long y;
};
 
bool pointOnSegment(const Point& p, const Point& q, const Point& r) {
    long long cross = (r.x - p.x) * (q.y - p.y) - (r.y - p.y) * (q.x - p.x);
    if (cross != 0)
        return false;
    
    if (min(p.x, r.x) <= q.x && q.x <= max(p.x, r.x) &&
        min(p.y, r.y) <= q.y && q.y <= max(p.y, r.y))
        return true;
    else
        return false;
}
 
string pointInPolygon(const Point& pt, const vector<Point>& polygon) {
    int n = polygon.size();
    bool onBoundary = false;
    int crossings = 0;
    
    for(int i = 0; i < n; ++i){
        int j = (i + 1) % n;
        Point p1 = polygon[i];
        Point p2 = polygon[j];
        
        if(pointOnSegment(p1, pt, p2)){
            onBoundary = true;
            break;
        }
        
        if( (p1.y <= pt.y && p2.y > pt.y) || (p2.y <= pt.y && p1.y > pt.y) ){
            double intersect_x;
            if(p2.y != p1.y){
                intersect_x = p1.x + (double)(p2.x - p1.x) * (pt.y - p1.y) / (p2.y - p1.y);
            } else {
                intersect_x = p1.x;
            }
            
            if(intersect_x > pt.x){
                crossings++;
            }
        }
    }
    
    if(onBoundary){
        return "BOUNDARY";
    }
    else{
        return (crossings % 2) ? "INSIDE" : "OUTSIDE";
    }
}
 
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    int n, m;
    cin >> n >> m;
    
    vector<Point> polygon(n);
    for(int i =0; i <n; ++i){
        cin >> polygon[i].x >> polygon[i].y;
    }
    
    vector<Point> queries(m);
    for(int i =0; i <m; ++i){
        cin >> queries[i].x >> queries[i].y;
    }
    
    for(int i =0; i <m; ++i){
        string res = pointInPolygon(queries[i], polygon);
        cout << res << "\n";
    }
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED