Submission #95480

# Submission time Handle Problem Language Result Execution time Memory
95480 2019-02-01T14:03:39 Z forestryks Printed Circuit Board (CEOI12_circuit) C++14
100 / 100
89 ms 7160 KB
#pragma GCC optimize("Ofast")
/**
 * Author: Sergey Kopeliovich ([email protected])
 */
 
#define VERSION "0.1.5"

#include <cassert>
#include <cstdio>
#include <algorithm>

/** Fast allocation */

#define FAST_ALLOCATOR_MEMORY (1024*1024*20)
#ifdef FAST_ALLOCATOR_MEMORY
    int allocator_pos = 0;
    char allocator_memory[(int)FAST_ALLOCATOR_MEMORY];
    inline void * operator new ( size_t n ) {
        char *res = allocator_memory + allocator_pos;
        allocator_pos += n;
        assert(allocator_pos <= (int)FAST_ALLOCATOR_MEMORY);
        return (void *)res;
    }
    inline void operator delete ( void * ) noexcept { }
    //inline void * operator new [] ( size_t ) { assert(0); }
    //inline void operator delete [] ( void * ) { assert(0); }
#endif

/** Fast input-output */

template <class T = int> inline T readInt();                        
inline double readDouble();
inline int readUInt();                   
inline int readChar(); // first non-blank character
inline void readWord( char *s ); 
inline bool readLine( char *s ); // do not save '\n'
inline bool isEof();
inline int getChar(); 
inline int peekChar();
inline bool seekEof();
inline void skipBlanks();

template <class T> inline void writeInt( T x, char end = 0, int len = -1 );
inline void writeChar( int x ); 
inline void writeWord( const char *s );
inline void writeDouble( double x, int len = 0 );
inline void flush();

static struct buffer_flusher_t {
    ~buffer_flusher_t() {
        flush();
    }
} buffer_flusher;

/** Read */

static const int buf_size = 4096;

static unsigned char buf[buf_size];
static int buf_len = 0, buf_pos = 0;

inline bool isEof() {
    if (buf_pos == buf_len) {
        buf_pos = 0, buf_len = fread(buf, 1, buf_size, stdin);
        if (buf_pos == buf_len)
            return 1;
    }
    return 0;
}

inline int getChar() { 
    return isEof() ? -1 : buf[buf_pos++];
}

inline int peekChar() { 
    return isEof() ? -1 : buf[buf_pos];
}

inline bool seekEof() { 
    int c;
    while ((c = peekChar()) != -1 && c <= 32)
        buf_pos++;
    return c == -1;
}

inline void skipBlanks() {
    while (!isEof() && buf[buf_pos] <= 32U)
        buf_pos++;
}

inline int readChar() {
    int c = getChar();
    while (c != -1 && c <= 32)
        c = getChar();
    return c;
}

inline int readUInt() {
    int c = readChar(), x = 0;
    while ('0' <= c && c <= '9')
        x = x * 10 + c - '0', c = getChar();
    return x;
}

template <class T>
inline T readInt() {
    int s = 1, c = readChar();
    T x = 0;
    if (c == '-')
        s = -1, c = getChar();
    else if (c == '+')
        c = getChar();
    while ('0' <= c && c <= '9')
        x = x * 10 + c - '0', c = getChar();
    return s == 1 ? x : -x;
}

inline double readDouble() {
    int s = 1, c = readChar();
    double x = 0;
    if (c == '-')
        s = -1, c = getChar();
    while ('0' <= c && c <= '9')
        x = x * 10 + c - '0', c = getChar();
    if (c == '.') {
        c = getChar();
        double coef = 1;
        while ('0' <= c && c <= '9')
            x += (c - '0') * (coef *= 1e-1), c = getChar();
    }
    return s == 1 ? x : -x;
}

inline void readWord( char *s ) { 
    int c = readChar();
    while (c > 32)
        *s++ = c, c = getChar();
    *s = 0;
}

inline bool readLine( char *s ) { 
    int c = getChar();
    while (c != '\n' && c != -1)
        *s++ = c, c = getChar();
    *s = 0;
    return c != -1;
}

/** Write */

static int write_buf_pos = 0;
static char write_buf[buf_size];

inline void writeChar( int x ) {
    if (write_buf_pos == buf_size)
        fwrite(write_buf, 1, buf_size, stdout), write_buf_pos = 0;
    write_buf[write_buf_pos++] = x;
}

inline void flush() {
    if (write_buf_pos) {
        fwrite(write_buf, 1, write_buf_pos, stdout), write_buf_pos = 0;
        fflush(stdout);
    }
}

template <class T> 
inline void writeInt( T x, char end, int output_len ) {
    if (x < 0)
        writeChar('-'), x = -x;

    char s[24];
    int n = 0;
    while (x || !n)
        s[n++] = '0' + x % 10, x /= 10;
    while (n < output_len)
        s[n++] = '0';
    while (n--)
        writeChar(s[n]);
    if (end)
        writeChar(end);
}

inline void writeWord( const char *s ) {
    while (*s)
        writeChar(*s++);
}

inline void writeDouble( double x, int output_len ) {
    if (x < 0)
        writeChar('-'), x = -x;
    int t = (int)x;
    writeInt(t), x -= t;
    writeChar('.');
    for (int i = output_len - 1; i > 0; i--) {
        x *= 10;
        t = std::min(9, (int)x);
        writeChar('0' + t), x -= t;
    }
    x *= 10;
    t = std::min(9, (int)(x + 0.5));
    writeChar('0' + t);
}


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

#define mp make_pair
#define pb push_back
#define FAST_IO ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define FILE_IO(x) freopen((string(x) + ".in").c_str(), "r", stdin); freopen((string(x) + ".out").c_str(), "w", stdout)
#define f first
#define s second
#define x1 x1qwer
#define y1 y1qwer
#define right right123
#define left left123
#define foreach(it, v) for (auto it : v)
#define rep(it, n) for (int it = 0; it < n; ++it)
#define forin(it, l, r) for (int it = l; it < r; ++it)
#define all(x) x.begin(), x.end()

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const double DINF = numeric_limits<double>::infinity();
const ll MOD = 1e9 + 7;
const double EPS = 1e-7;
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
mt19937 mmtw_(MOD);
uniform_int_distribution<ll> rd_;
ll randomll() { return rd_(mmtw_);}
ll rnd(ll x, ll y) { return rd_(mmtw_) % (y - x + 1) + x; }
////////////////////////////////////////////////////////////////////////////////////////////////

struct pt {
    int x, y;
    int id;
};

inline bool operator==(const pt &a, const pt &b) {
    return a.x == b.x && a.y == b.y;
}

inline pt operator-(const pt &a) {
    return {-a.x, -a.y};
}

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

inline ll dot(const pt &a, const pt &b) {
    return 1LL * a.x * b.x + 1LL * a.y * b.y;
}

inline ll cross(const pt &a, const pt &b) {
    return 1LL * a.x * b.y - 1LL * a.y * b.x;
}

inline ll dd0(const pt &a) {
    return dot(a, a);
}

const int MAXN = 2e5 + 5;
int n;
pt a[MAXN];
bool used[MAXN];
int ord[MAXN];

inline int md(int x) {
    if (x >= n) return x - n;
    if (x < 0) return x + n;
    return x;
}

int findLowest() {
    int s = 0;
    for (int i = 0; i < n; ++i) {
        ll cr = cross(a[i], a[s] - a[i]);
        if (cr > 0 || (cr == 0 && dd0(a[i]) < dd0(a[s]))) {
            s = i;
        }
    }
    return s;
}

int findHighest() {
    int t = 0;
    for (int i = 0; i < n; ++i) {
        ll cr = cross(a[i], a[t] - a[i]);
        if (cr < 0 || (cr == 0 && dd0(a[i]) < dd0(a[t]))) {
            t = i;
        }
    }
    return t;
}

struct cmp {
    bool operator()(int i, int j) {
        if (i == j) return false;
        if (cross(a[i], a[j]) <= 0) {
            return cross(a[j + 1] - a[j], a[i] - a[j]) > 0;
        } else {
            return cross(a[i + 1] - a[i], a[j] - a[i]) < 0;
        }
    }
};

signed main() {
    // FAST_IO;
    // cin >> n;
    n = readInt();
    rep(i, n) {
        // cin >> a[i].x >> a[i].y;
        a[i].x = readInt();
        a[i].y = readInt();
        a[i].id = i + 1;
    }

    assert(n > 2);

    int lowest = findLowest();
    if (cross(a[md(lowest - 1)] - a[lowest], a[md(lowest + 1)] - a[lowest]) < 0) {
        reverse(a, a + n);
    }

    rotate(a, a + findLowest(), a + n);
    n = findHighest() + 1;

    for (int i = 0; i < n; ++i) {
        ord[i] = i;
    }

    sort(ord, ord + n, [](int i, int j){
        ll cr = cross(a[i], a[j]);
        if (cr != 0) return cr > 0;
        return dd0(a[i]) < dd0(a[j]);
    });

    vector<int> res;
    set<int, cmp> s;
    for (int ii = 0; ii < n; ++ii) {
        int i = ord[ii];

        bool add = (i + 1 < n && cross(a[i], a[i + 1] - a[i]) > 0);

        if (used[i]) {
            s.erase(s.find(i - 1));
        }

        if (!s.empty()) {
            int f = *s.begin();
            if (cross(a[f + 1] - a[f], a[i] - a[f]) > 0) res.push_back(a[i].id);
        } else {
            res.push_back(a[i].id);
        }

        if (add) {
            s.insert(i);
            used[i + 1] = true;
        }
    }

    sort(all(res));

    // cout << res.size() << '\n';
    writeInt(res.size(), '\n');
    for (auto it : res) {
        // cout << it << ' ';
        writeInt(it, ' ');
    }
    // cout << '\n';
    writeChar('\n');
}
# Verdict Execution time Memory Grader output
1 Correct 2 ms 380 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 508 KB Output is correct
4 Correct 2 ms 632 KB Output is correct
5 Correct 4 ms 632 KB Output is correct
6 Correct 6 ms 632 KB Output is correct
7 Correct 7 ms 932 KB Output is correct
8 Correct 4 ms 632 KB Output is correct
9 Correct 4 ms 760 KB Output is correct
10 Correct 5 ms 632 KB Output is correct
11 Correct 5 ms 760 KB Output is correct
12 Correct 6 ms 1016 KB Output is correct
13 Correct 11 ms 1272 KB Output is correct
14 Correct 8 ms 1400 KB Output is correct
15 Correct 11 ms 1912 KB Output is correct
16 Correct 21 ms 3580 KB Output is correct
17 Correct 31 ms 2936 KB Output is correct
18 Correct 38 ms 6392 KB Output is correct
19 Correct 44 ms 7160 KB Output is correct
20 Correct 89 ms 6644 KB Output is correct