Submission #394274

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
394274	2021-04-26T10:19:03 Z	Drew_	Aliens (IOI16_aliens)	C++17	Compilation error	0 ms	0 KB

aliens

#include "aliens.h"
#include <vector>
#include <iostream>
#include <algorithm>
#include <cassert>
using namespace std;

#define ll long long
#define pb push_back
#define ii pair<int, int>
#define pl pair<ll, ll>
#define f1 first
#define s2 second

const int MAX = 1e5 + 7;

struct Line
{
	ll m, c;
	Line() : m(0), c(0) {}
	Line(ll m, ll c) : m(m), c(c) {}
	double inter(const Line &other) { return (double) (c - other.c) / (other.m - m); }
};

struct convex_hull
{
	int sz = 0;
	Line ar[MAX];

	void clear() { sz = 0; }
	bool cmp(Line a, Line b, Line c) { return a.inter(b) < b.inter(c); }
	void addLine(ll m, ll c)
	{
		Line L(m, c);
		while (sz >= 2 && !cmp(ar[sz-2], ar[sz-1], L))
			sz--;
		ar[sz++] = L;
	}

	ll query(ll x)
	{
		int l = 0, r = sz-1;
		while (l < r)
		{
			int mid = (l + r) / 2;
			if (ar[mid].inter(ar[mid+1]) >= x) r = mid;
			else l = mid + 1;
		}
		return ar[l].m * x + ar[l].c;
	}
} cht;

vector<pl> ivl;
//cost for interval [i, j], assuming interval [0, i-1] have been fulfilled
/*
inline ll getCost(int i, int j)
{
	ll res = 1LL * (ivl[j].s2 - ivl[i].f1 + 1) * (ivl[j].s2 - ivl[i].f1 + 1);
	if (i)
	{
		if (ivl[i-1].s2 >= ivl[i].f1)
			res -= 1LL * (ivl[i-1].s2 - ivl[i].f1 + 1) * (ivl[i-1].s2 - ivl[i].f1 + 1);
	}
	return res;
}
*/

ll dp[2][MAX];
long long take_photos(int n, int m, int k, std::vector<int> r, std::vector<int> c) {
	vector<ii> v(n);
	for (int i = 0; i < n; ++i)
		v[i] = {min(r[i], c[i]), max(r[i], c[i])};
	sort(v.begin(), v.end(), [](const ii &x, const ii &y){
		return x.f1 < y.f1 || (x.f1 == y.f1 && x.s2 > y.s2);
	});

	ivl.pb(v[0]);
	for (int i = 1; i < n; ++i)
	{
		if (ivl.back().f1 <= v[i].f1 && v[i].s2 <= ivl.back().s2)
			continue;
		ivl.pb(v[i]);
	}

	for (int i = 0; i < ivl.size(); ++i)
		dp[0][i] = (ivl[i].s2 - ivl[0].f1 + 1) * (ivl[i].s2 - ivl[0].f1 + 1);

	k = min(k, (int)ivl.size());
	for (int j = 1; j < k; ++j)
	{
		cht.clear();
		cht.addLine(-2 * ivl[0].f1, ivl[0].f1 * ivl[0].f1);
		for (int i = 1; i < ivl.size(); ++i)
		{
			ll m = -2 * ivl[i].f1;
			ll c = (ivl[i].f1 * ivl[i].f1) + dp[~j & 1][i-1];
			if (ivl[i].f1 <= ivl[i-1].s2)
				c -= (ivl[i-1].s2 - ivl[i].f1 + 1) * ((ivl[i-1].s2 - ivl[i].f1 + 1));
			cht.addLine(m, c);

			dp[j&1][i] = cht.query(ivl[i].s2 + 1) + (ivl[i].s2 + 1) * (ivl[i].s2 + 1);
		}
	}

	return dp[~k & 1][ivl.size() - 1];
	/*
	ll L = 0, R = 1e12;
	for (int i = 0; i < ivl.size(); ++i)
		L = max(L, getCost(i, i));
	k = min(k, (int)ivl.size());
	while (L < R)
	{
		ll mid = (L + R) / 2;
		pl res = check(mid);

		if (res.f1 <= k) R = mid;
		else L = mid + 1;
	}
	pl res = check(L);
	return k * L + res.s2;
	*/
}


int main() {
    int n, m, k;
    assert(3 == scanf("%d %d %d", &n, &m, &k));
    std::vector<int> r(n), c(n);
    for (int i = 0; i < n; i++) {
        assert(2 == scanf("%d %d", &r[i], &c[i]));
    }
    long long ans = take_photos(n, m, k, r, c);
    
    
    printf("%lld\n", ans);
    return 0;
}

Compilation message

aliens.cpp: In function 'long long int take_photos(int, int, int, std::vector<int>, std::vector<int>)':
aliens.cpp:85:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   85 |  for (int i = 0; i < ivl.size(); ++i)
      |                  ~~^~~~~~~~~~~~
aliens.cpp:93:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   93 |   for (int i = 1; i < ivl.size(); ++i)
      |                   ~~^~~~~~~~~~~~
/tmp/cctljyjZ.o: In function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'
/tmp/ccxyqHCW.o:aliens.cpp:(.text.startup+0x0): first defined here
collect2: error: ld returned 1 exit status