Submission #1385068

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
#define fi first
#define se second

template<typename A, typename B> inline bool chmax(A &a, B b) { if (a<b) { a=b; return 1; } return 0; }
template<typename A, typename B> inline bool chmin(A &a, B b) { if (a>b) { a=b; return 1; } return 0; }

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
//typedef pair<int, pll> P;
const ll INF = 1ll<<30;
const ll MOD = 1000000007;
const double EPS  = 1e-10;

typedef complex<double> P;
typedef complex<double> Vec;

double cross(Vec a, Vec b) {
	return a.real() * b.imag() - a.imag() * b.real();
}

bool comp(P a, P b) {
	if (a.real() != b.real()) return a.real() < b.real();
	return a.imag() < b.imag();
}

vector<P> convex_full(vector<P> p) {
	sort(ALL(p), comp);
	
	vector<P> res(2 * p.size());
	int k = 0;
	
	// 下側凸包
	REP(i, p.size()) {
		while (k > 1 && cross(res[k - 1] - res[k - 2], p[i] - res[k - 2]) <= 0) k--;
		res[k++] = p[i];
	}
	
	int c1 = k;
	
	// 上側凸包
	for (int i = (int)p.size() - 2; i >= 0; i--) {
		while (k > c1 && cross(res[k - 1] - res[k - 2], p[i] - res[k - 2]) <= 0) k--;
		res[k++] = p[i];
	}
	
	res.resize(k);
	return res;
}

int main() {
	int N;
	vector<P> p[2];
	
	cin >> N;
	REP(i, 2) {
		REP(j, N) {
			int a, b;
			scanf("%d %d", &a, &b);
			p[i].push_back(P(a, b));
		}
	}
	
	double l[2] = {};
	REP(i, 2) {
		vector<P> cf = convex_full(p[i]);
		REP(j, cf.size()) l[i] += abs(cf[(j + 1) % cf.size()] - cf[j]);
	}
	
	printf("%.15f\n", l[1] / l[0]);
	
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:66:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
    scanf("%d %d", &a, &b);
                          ^

Judge Result