Submission #964412

#	Time	Username	Problem	Language	Result	Execution time	Memory
964412		BestCrazyNoob	Seats (IOI18_seats)	C++17	11 / 100	4029 ms	39504 KiB

seats

#include "seats.h"
#include <cassert>
#include <tuple>

using namespace std;

struct Node {
    int mn, mx;
    Node(): mn(1e9), mx(0) {}
    Node(int a): mn(a), mx(a) {}
    Node(Node l, Node r) {
        mn = min(l.mn, r.mn);
        mx = max(l.mx, r.mx);
    }
};

struct SegTree {
    int sz;
    vector<Node> tree;
    int ql, qr;
    SegTree() {}
    SegTree(vector<int> v) {
        sz = 1;
        while (sz < v.size()) sz *= 2;
        tree.resize(2*sz, Node());
        for (int i = 0; i < v.size(); i++) tree[sz+i] = Node(v[i]);
        for (int i = v.size(); i < sz; i++) tree[sz+i] = Node();
        for (int i = sz-1; i >= 1; i--) tree[i] = Node(tree[2*i], tree[2*i+1]);
    }
    void update(int i, int x) {
        i += sz;
        tree[i] = Node(x);
        while (i > 1) {
            i /= 2;
            tree[i] = Node(tree[2*i], tree[2*i+1]);
        }
    }
    Node __query(int ni, int nl, int nr) {
        if (qr <= nl || nr <= ql) return Node();
        if (ql <= nl && nr <= qr) return tree[ni];
        int nm = (nl+nr)/2;
        return Node(__query(2*ni, nl, nm), __query(2*ni+1, nm, nr));
    }
    pair<int, int> query(int l, int r) {
        ql = l;
        qr = r;
        auto res = __query(1, 0, sz);
        return {res.mn, res.mx};
    }
};

// sol1
vector<int> mxC, mnC, mxR, mnR;
int ans;

// sol2
vector<int> R, C;
SegTree rSeg, cSeg;

void give_initial_chart(int H, int W, vector<int> R, vector<int> C) {
    assert(H <= 10'000);
    assert(W <= 10'000);
    ::R = R;
    ::C = C;
    if (C.size() > 1'000 || R.size() > 1'000) {
        // sol1
        mxC.resize(C.size());
        mnC.resize(C.size());
        mxR.resize(C.size());
        mnR.resize(C.size());
        mxC[0] = mnC[0] = C[0];
        mxR[0] = mnR[0] = R[0];
        for (int i = 1; i < C.size(); i++) {
            mxC[i] = max(C[i], mxC[i-1]);
            mxR[i] = max(R[i], mxR[i-1]);
            mnC[i] = min(C[i], mnC[i-1]);
            mnR[i] = min(R[i], mnR[i-1]);
        }
        for (int i = 0; i < C.size(); i++) {
            ans += (mxC[i] - mnC[i] + 1) * (mxR[i] - mnR[i] + 1) == i+1;
        }
    } else {
        // sol2
        rSeg = SegTree(R);
        cSeg = SegTree(C);
    }
}

int sol1(int a, int b) {
    // a < b WLOG
    if (a > b) swap(a, b);

    for (int i = a; i <= b; i++) {
        ans -= (mxC[i] - mnC[i] + 1) * (mxR[i] - mnR[i] + 1) == i+1;
    }

    swap(R[a], R[b]);
    swap(C[a], C[b]);
    if (a == 0) {
        mxC[0] = mnC[0] = C[0];
        mxR[0] = mnR[0] = R[0];
    }
    for (int i = max(1, a); i <= b; i++) {
        mxC[i] = max(C[i], mxC[i-1]);
        mxR[i] = max(R[i], mxR[i-1]);
        mnC[i] = min(C[i], mnC[i-1]);
        mnR[i] = min(R[i], mnR[i-1]);
    }

    for (int i = a; i <= b; i++) {
        ans += (mxC[i] - mnC[i] + 1) * (mxR[i] - mnR[i] + 1) == i+1;
    }
    return ans;
}

int sol2(int a, int b) {
    // update
    swap(R[a], R[b]);
    swap(C[a], C[b]);
    rSeg.update(a, R[a]);
    rSeg.update(b, R[b]);
    cSeg.update(a, C[a]);
    cSeg.update(b, C[b]);
    // query
    int i = 1, ans = 1;
    int mnR = R[0], mnC = C[0], mxR = R[0], mxC = C[0];
    while (i < C.size()) {
        tie(mnR, mxR) = rSeg.query(0, i);
        tie(mnC, mxC) = cSeg.query(0, i);
        if ((mxR - mnR + 1) * (mxC - mnC + 1) == i) {
            ans++;
            i += min(mxR - mnR + 1, mxC - mnC + 1);
        } else {
            i = (mxR - mnR + 1) * (mxC - mnC + 1);
        }
    }
    return ans;
}

int swap_seats(int a, int b) {
    if (C.size() > 1'000 || R.size() > 1'000) return sol1(a, b);
    return sol2(a, b);
}

Compilation message (stderr)

seats.cpp: In constructor 'SegTree::SegTree(std::vector<int>)':
seats.cpp:24:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |         while (sz < v.size()) sz *= 2;
      |                ~~~^~~~~~~~~~
seats.cpp:26:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 |         for (int i = 0; i < v.size(); i++) tree[sz+i] = Node(v[i]);
      |                         ~~^~~~~~~~~~
seats.cpp: In function 'void give_initial_chart(int, int, std::vector<int>, std::vector<int>)':
seats.cpp:73:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   73 |         for (int i = 1; i < C.size(); i++) {
      |                         ~~^~~~~~~~~~
seats.cpp:79:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   79 |         for (int i = 0; i < C.size(); i++) {
      |                         ~~^~~~~~~~~~
seats.cpp: In function 'int sol2(int, int)':
seats.cpp:127:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  127 |     while (i < C.size()) {
      |            ~~^~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 6 / 6
• Subtask 3: 0 / 20
• Subtask 4: 0 / 6
• Subtask 5: 0 / 33
• Subtask 6: 0 / 30