Function

input/code.cpp: In function 'void solve()':
input/code.cpp:116:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 3; i < v.size(); i++) {
                    ~~^~~~~~~~~~
input/code.cpp:91:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
input/code.cpp:93:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%lld %lld", &a[i].x, &a[i].y);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
input/code.cpp: In function 'int main(int, const char**)':
input/code.cpp:128:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &t);
     ~~~~~^~~~~~~~~~

#include "bits/stdc++.h"
using namespace std;

struct Point {
    long long x, y;
    Point (long long x, long long y) : x(x), y(y) {}
    Point () {}
    Point operator + (Point p) {
        return Point(x + p.x, y + p.y);
    }
    Point operator - (Point p) {
        return Point(x - p.x, y - p.y);
    }
} a[1000010];

long long cross(Point p, Point q) {
    return p.x * q.y - q.x * p.y;
}

// Given three colinear points p, q, r, the function checks if 
// point q lies on line segment 'pr' 
bool onSegment(Point p, Point q, Point r) 
{ 
    if (q.x <= max(p.x, r.x) && q.x >= min(p.x, r.x) && 
        q.y <= max(p.y, r.y) && q.y >= min(p.y, r.y)) 
       return true; 
  
    return false; 
} 
  
// To find orientation of ordered triplet (p, q, r). 
// The function returns following values 
// 0 --> p, q and r are colinear 
// 1 --> Clockwise 
// 2 --> Counterclockwise 
int orientation(Point p, Point q, Point r) 
{ 
    // See https://www.geeksforgeeks.org/orientation-3-ordered-points/ 
    // for details of below formula. 
    long long val = (q.y - p.y) * (r.x - q.x) - 
              (q.x - p.x) * (r.y - q.y); 
  
    if (val == 0) return 0;  // colinear 
  
    return (val > 0)? 1: 2; // clock or counterclock wise 
} 
  
// The main function that returns true if line segment 'p1q1' 
// and 'p2q2' intersect. 
bool doIntersect(Point p1, Point q1, Point p2, Point q2) 
{ 
    // Find the four orientations needed for general and 
    // special cases 
    int o1 = orientation(p1, q1, p2); 
    int o2 = orientation(p1, q1, q2); 
    int o3 = orientation(p2, q2, p1); 
    int o4 = orientation(p2, q2, q1); 
  
    // General case 
    if (o1 != o2 && o3 != o4) 
        return true; 
  
    // Special Cases 
    // p1, q1 and p2 are colinear and p2 lies on segment p1q1 
    if (o1 == 0 && onSegment(p1, p2, q1)) return true; 
  
    // p1, q1 and q2 are colinear and q2 lies on segment p1q1 
    if (o2 == 0 && onSegment(p1, q2, q1)) return true; 
  
    // p2, q2 and p1 are colinear and p1 lies on segment p2q2 
    if (o3 == 0 && onSegment(p2, p1, q2)) return true; 
  
     // p2, q2 and q1 are colinear and q1 lies on segment p2q2 
    if (o4 == 0 && onSegment(p2, q1, q2)) return true; 
  
    return false; // Doesn't fall in any of the above cases 
} 

bool inside(Point a, Point b, Point c) {
    long long A = abs(cross(a, b));
    long long B = abs(cross(c, a - c)) + abs(cross(c, b - c)) + abs(cross(a - c, b - c));
    if(A == B) return true;
    if(doIntersect(a, b, c, Point(0, 0))) return true;
    return false;
}

bool bad[1000010];

void solve() {
    int n;
    scanf("%d", &n);
    for(int i = 1; i <= n; i++) {
        scanf("%lld %lld", &a[i].x, &a[i].y);
        bad[i] = false;
    }
    vector <Point> v;
    for(int i = 2; i < n; i++) {
        if(cross(a[i - 1] - a[i], a[i + 1] - a[i]) == 0) {
            if(!onSegment(a[i - 1], a[i], a[i + 1])) {
                printf("NO\n");
                return ;
            } 
            bad[i] = true;
        }
    }
    for(int i = 2; i <= n; i++) {
        if(a[i - 1].x == a[i].x && a[i - 1].y == a[i].y) {
            bad[i - 1] = true;
        }
    }
    for(int i = 1; i <= n; i++) {
        if(!bad[i]) {
            v.emplace_back(a[i]);
        }
    }
    for(int i = 3; i < v.size(); i++) {
        if(inside(v[i - 1] - v[i - 2], v[i] - v[i - 1], v[i - 3] - v[i - 2])) {
            printf("NO\n");
            return ;
        }
    }
    printf("YES\n");
}

int main(int argc, char const *argv[])
{
    int t;
    scanf("%d", &t);
    while(t--) {
        solve();
    }    
    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: WRONG ANSWER

Test 7

Group: 1

Verdict: WRONG ANSWER

Test 8

Group: 1

Verdict: ACCEPTED

Test 9

Group: 1

Verdict: WRONG ANSWER

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 2

Verdict: ACCEPTED

Test 12

Group: 2

Verdict: ACCEPTED

Test 13

Group: 2

Verdict: ACCEPTED

Test 14

Group: 2

Verdict: ACCEPTED

Test 15

Group: 2

Verdict: WRONG ANSWER

Test 16

Group: 2

Verdict: WRONG ANSWER

Test 17

Group: 2

Verdict: WRONG ANSWER

Test 18

Group: 2

Verdict: WRONG ANSWER

Test 19

Group: 2

Verdict: WRONG ANSWER

Test 20

Group: 2

Verdict: WRONG ANSWER

Test 21

Group: 2

Verdict: ACCEPTED

Test 22

Group: 2

Verdict: WRONG ANSWER

Test 23

Group: 2

Verdict: ACCEPTED

Test 24

Group: 2

Verdict: ACCEPTED

Test 25

Group: 2

Verdict: ACCEPTED

Test 26

Group: 2

Verdict: WRONG ANSWER

Test 27

Group: 2

Verdict: WRONG ANSWER

Test 28

Group: 2

Verdict: ACCEPTED

Test 29

Group: 2

Verdict: WRONG ANSWER

Test 30

Group: 2

Verdict: ACCEPTED

Test 31

Group: 2

Verdict: ACCEPTED

Test 32

Group: 2

Verdict: ACCEPTED

Test 33

Group: 2

Verdict: WRONG ANSWER

Test 34

Group: 2

Verdict: ACCEPTED

Test 35

Group: 2

Verdict: ACCEPTED