Submission #1114730

#	Time	Username	Problem	Language	Result	Execution time	Memory
1114730		PVSekhar	Walk (CEOI06_walk)	C++17	0 / 100	50 ms	11240 KiB

walk

#include <bits/stdc++.h>
using namespace std; 
#define ll long long
// const ll MOD = 998244353;
const ll MOD = 1e9 + 7;
const ll N = 1e6 + 2;
const ll INF = 1e18 + 2;

// from jiangly's template
const double TOL = 1e-9;

template<class T>
struct Point {
    T x;
    T y;
    Point(const T x_ = 0, const T y_ = 0) : x(x_), y(y_) {}


    template<class U>
    operator Point<U>() {
        return Point<U>(U(x), U(y));
    }
    Point &operator+=(const Point &p) & {
        x += p.x;
        y += p.y;
        return *this;
    }
    Point &operator-=(const Point &p) & {
        x -= p.x;
        y -= p.y;
        return *this;
    }
    Point &operator*=(const T &v) & {
        x *= v;
        y *= v;
        return *this;
    }
    Point &operator/=(const T &v) & {
        x /= v;
        y /= v;
        return *this;
    }
    Point operator-() const {
        return Point(-x, -y);
    }
    friend Point operator+(Point a, const Point &b) {
        return a += b;
    }
    friend Point operator-(Point a, const Point &b) {
        return a -= b;
    }
    friend Point operator*(Point a, const T &b) {
        return a *= b;
    }
    friend Point operator/(Point a, const T &b) {
        return a /= b;
    }
    friend Point operator*(const T &a, Point b) {
        return b *= a;
    }
    // w/o tolerance
    // friend bool operator<(const Point &a, const Point &b) {
    //     return a.x < b.x || (a.x == b.x && a.y < b.y);
    // }
    // w/ tolerance
    friend bool operator<(const Point &a, const Point &b) {
        return (a.x < b.x || (abs(a.x - b.x) < TOL && a.y < b.y));
    }
    friend bool operator>(const Point &a, const Point &b) {
        return !(a < b);
    }
    // without tolerance
    friend bool operator==(const Point &a, const Point &b) {
        return a.x == b.x && a.y == b.y;
    }
    friend bool operator!=(const Point &a, const Point &b) {
        return !(a.x == b.x && a.y == b.y);
    }


    // with tolerance
    // friend bool operator==(const Point &a, const Point &b) {
    //     Point<T> p = a - b;
    //     T len = sqrt(p.x * p.x + p.y * p.y);
    //     return len < TOL;
    // }
    // friend bool operator!=(const Point &a, const Point &b) {
    //     Point<T> p = a - b;
    //     T len = sqrt(p.x * p.x + p.y * p.y);
    //     return !(len < TOL);
    // }
    friend std::istream &operator>>(std::istream &is, Point &p) {
        return is >> p.x >> p.y;
    }
    friend std::ostream &operator<<(std::ostream &os, const Point &p) {
        return os << "(" << p.x << ", " << p.y << ")";
    }
};

//For sweep line

// struct Segment{
//     ll x1, y1, x2, y2, ind;

//     double coordinate() const {
//         if (x1 == x2) { return y1; }
//         return y1 + 1.0 * (y2 - y1) * (cur_x - x1) / (x2 - x1);
//     }
//     bool operator<(Segment const& o) const {
//         return ind != o.ind && (coordinate() <= o.coordinate());
//     }
//     bool operator==(const Segment &l) const {
//         return ind == l.ind;
//     }
// };

using Pt = Point<ll>;

ll cur_x = 0, x, y, n;
vector<Pt> pts;
map<Pt, Pt> par; // x, y
map<Pt, ll> dis; // x, y
set<pair<ll, ll>> store; // y, x

void update(Pt &p, pair<ll, ll> &near) {
    if (near.first == p.y) store.erase(near);
    if (near.second != p.x) par[p] = Pt(near.second, near.first);
    else par[p] = par[Pt(near.second, near.first)];
}

void solve(Pt &p) {
    pair<ll, ll> l = make_pair(-1, -1), r = make_pair(-1, -1);
    auto it = store.end();
    it = upper_bound(store.begin(), store.end(), make_pair(p.y, INF));
    if (it != store.begin()) l = *(--it);
    it = upper_bound(store.begin(), store.end(), make_pair(p.y, -1ll));
    if (it != store.end()) r = *it;
    // cout << p.x << " " << p.y << " l: " << l.first << " " << l.second << " r: " << r.first << " " << r.second << "\n";
    if (l.first == -1) {
        dis[p] = dis[Pt(r.second, r.first)] + abs(p.y - r.first);
        update(p, r);
    } else if (r.first == -1) {
        dis[p] = dis[Pt(l.second, l.first)] + abs(p.y - l.first);
        update(p, l);
    } else {
        ll d1 = dis[Pt(l.second, l.first)] + abs(p.y - l.first), d2 = dis[Pt(r.second, r.first)] + abs(p.y - r.first);
        if (d1 <= d2) {
            dis[p] = d1;
            update(p, l);
        } else {
            dis[p] = d2;
            update(p, r);
        }
    }
    store.insert(make_pair(p.y, p.x));
}

void solve(Pt &p, Pt &q) {
    solve(p);
    solve(q);
    auto it = store.find(make_pair(q.y, q.x));
    pair<ll, ll> pa = make_pair(p.y, p.x);
    while (*(--it) != pa) {
        store.erase(*it);
    }
}

void solve() {
    ll x1, y1, x2, y2;
    cin >> x >> y >> n;
    y += N;
    for (int i = 0; i < n; i++) {
        cin >> x1 >> y1 >> x2 >> y2;
        y1 += N;
        y2 += N;
        pts.push_back(Pt(x1 - 1, y1 - 1));
        pts.push_back(Pt(x1 - 1, y2 + 1));
    }
    sort(pts.begin(), pts.end());
    store.insert(make_pair(N, 0));
    dis[Pt(N, 0)] = 0;
    for (int i = 0; i < 2 * n; i += 2) {
        if (pts[i].x == x) break;
        solve(pts[i], pts[i + 1]);
    }
    Pt dest = Pt(x, y), prev;
    solve(dest);
    cout << dis[dest] + x << "\n";
    stack<Pt> st;
    st.push(Pt(dest.x, dest.y - N));
    while (dest != Pt(0, N)) {
        dest = par[dest];
        st.push(Pt(dest.x, dest.y - N));
    }
    vector<pair<ll, ll>> ans;
    deque<pair<ll, ll>> dir;
    prev = Pt(0, 0);
    st.pop();
    while (!st.empty()) {
        dest = st.top();
        // cout << dest.x << " " << dest.y << " " << prev.x << " " << prev.y << "\n";
        ans.push_back(make_pair(dest.x - prev.x, 0ll));
        ans.push_back(make_pair(0ll, dest.y - prev.y));
        st.pop();
        prev = dest;
    }
    dir.push_back(ans[0]); 
    for (int i = 0; i + 1 < ans.size(); i += 2) {
        if (ans[i] != make_pair(0ll, 0ll)) {
            dir.push_back(ans[i + 1]);
        } else {
            dir.pop_back();
            if (dir.empty()) dir.push_back(ans[i + 1]);
            else dir.back().second += ans[i + 1].second;
        }
        if (i + 2 < ans.size()) dir.push_back(ans[i + 2]);
    }
    cout << dir.size() << "\n";
    while (!dir.empty()) {
        cout << dir.front().first << " " << dir.front().second << "\n";
        dir.pop_front();
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    ll t;
    t = 1;
    // cin >> t;
    while(t--) {
        solve();
    }
    return 0;
}

Compilation message (stderr)

walk.cpp: In function 'void solve()':
walk.cpp:208:27: 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]
  208 |     for (int i = 0; i + 1 < ans.size(); i += 2) {
      |                     ~~~~~~^~~~~~~~~~~~
walk.cpp:216:19: 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]
  216 |         if (i + 2 < ans.size()) dir.push_back(ans[i + 2]);
      |             ~~~~~~^~~~~~~~~~~~

• Subtask 1: 0 / 100