Submission #1561836

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Source Code Expand

#include <algorithm>
#include <cstdio>
#include <cstring>
#include <vector>

struct Point
{
    Point(int x = 0, int y = 0) : x(x), y(y) {}

    int x, y;
};

Point operator - (const Point& a, const Point& b)
{
    return Point(a.x - b.x, a.y - b.y);
}

int det(const Point& a, const Point& b)
{
    return a.x * b.y - a.y * b.x;
}

int dot(const Point& a, const Point& b)
{
    return a.x * b.x + a.y * b.y;
}

const int N = 200;
const int MOD = 998244353;

int pw[N + 1];
Point p[N];

int main()
{
#ifdef LOCAL_JUDGE
    freopen("C.in", "r", stdin);
#endif
    int n;
    while (scanf("%d", &n) == 1) {
        for (int i = 0; i < n; ++ i) {
            scanf("%d%d", &p[i].x, &p[i].y);
        }
        pw[0] = 1;
        for (int i = 1; i <= n; ++ i) {
            pw[i] = pw[i - 1] * 2 % MOD;
        }
        int result = pw[n];
        (result += MOD - 1 - n) %= MOD;
        for (int i = 0; i < n; ++ i) {
            for (int j = i + 1; j < n; ++ j) {
                int cnt = 0;
                for (int k = 0; k < n; ++ k) {
                    cnt += det(p[k] - p[i], p[k] - p[j]) == 0 && dot(p[k] - p[i], p[k] - p[j]) < 0;
                }
                result += MOD - pw[cnt];
                if (result >= MOD) {
                    result -= MOD;
                }
            }
        }
        printf("%d\n", result);
    }
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:42:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d%d", &p[i].x, &p[i].y);
                                            ^

Judge Result