Submission #95480

#	Time	Username	Problem	Language	Result	Execution time	Memory
95480		forestryks	Printed Circuit Board (CEOI12_circuit)	C++14	100 / 100	89 ms	7160 KiB

circuit

#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');
}

• Subtask 1: 100 / 100