Point in Polygon

input/code.cpp: In function 'int main()':
input/code.cpp:55:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<pt>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   55 |         for(int i=0; i<ps.size(); i++){
      |                      ~^~~~~~~~~~
input/code.cpp:57:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<pt>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |             pt b = (i == ps.size() -1 ? ps[0] : ps[i+1]);
      |                     ~~^~~~~~~~~~~~~~~

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;

struct pt{ ll x; ll y; };
pt operator+(const pt& a, const pt& b){ return pt{.x=a.x+b.x, .y=a.y+b.y}; };
pt operator-(const pt& a, const pt& b){ return pt{.x=a.x-b.x, .y=a.y-b.y}; };
bool operator==(const pt& a, const pt& b){ return a.x == b.x && a.y == b.y; };
ostream& operator<<(ostream& os, const pt& a){ return os << "(" << a.x << "," << a.y << ")"; }
ll cross(pt p1, pt p2){
    return p1.x*p2.y - p1.y*p2.x;
}
ll orient(pt a, pt b, pt c) {
    return cross(b-a, c-a);
}
ll dot(pt a, pt b){
    return a.x*b.x+a.y*b.y;
}

int isintersect(pt p, pt a, pt b){
    if(a.y > b.y) swap(a.y, b.y);
    int r = a.x >= p.x && b.x >= p.x && a.y <= p.y && b.y >= p.y;
    pt d1 = a - p;
    pt d2 = b - p;
    ll dp = dot(d1, d2);
    int r2 = (dp <= 0 && cross(d1,d2) == 0 ? 10 : 0);
    // if(r2){
    //     cout << "here: " << d1 << " " << d2 << " " << dp << " " << cross(d1,d2) << " " << r2 << "\n";
    // }
    return r + r2;
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);

    int n,m;
    cin >> n >> m;

    vector<pt> ps;
    ps.reserve(n);
    for(int i=0; i<n; i++){
        ll x, y;
        cin >> x >> y;
        ps.push_back({x,y});
    }

    for(int k=0; k<m; k++){
        pt p;
        cin >> p.x >> p.y;

        int ci = 0;
        int br = 0;
        for(int i=0; i<ps.size(); i++){
            pt a = ps[i];
            pt b = (i == ps.size() -1 ? ps[0] : ps[i+1]);
            // cout << "this: " << i << " " << a << " " << b << endl;

            auto r = (isintersect(p,a,b));
            ci += r;
            if(r > 1){
                cout << "BOUNDARY\n";
                br = 1;
                break;
            }
        }

        if(br)continue;
        cout << (ci % 2 == 0 ? "OUTSIDE" : "INSIDE") << "\n";
    }
}

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: ACCEPTED

Test 13

Verdict: WRONG ANSWER