Submission #1010943

#	Time	Username	Problem	Language	Result	Execution time	Memory
1010943		boris_mihov	Seats (IOI18_seats)	C++17	33 / 100	1053 ms	191516 KiB

seats

#include "seats.h"
#include <algorithm>
#include <iostream>
#include <numeric>
#include <cassert>
#include <vector>

typedef long long llong;
const int MAXN = 1000000 + 10;
const int INF  = 1e9;

int n, m;
struct SegmentTreeLazy
{
    struct Node
    {
        int min;
        int cnt;
        int lazy;
        
        Node()
        {
            min = cnt = lazy = 0;
        }
    
        friend Node operator + (const Node &left, const Node &right)
        {
            Node res;
            res.min = std::min(left.min, right.min);
            if (res.min == left.min) res.cnt += left.cnt;
            if (res.min == right.min) res.cnt += right.cnt;
            return res;
        }
    };

    Node tree[4*MAXN];
    void build(int l, int r, int node)
    {
        if (l == r)
        {
            tree[node].min = 0;
            tree[node].cnt = 1;
            return;
        }

        int mid = l + r >> 1;
        build(l, mid, 2*node);
        build(mid + 1, r, 2*node + 1);
        tree[node] = tree[2*node] + tree[2*node + 1];
    }

    void push(int node, int l, int r)
    {
        if (tree[node].lazy == 0)
        {
            return;
        }

        tree[node].min += tree[node].lazy;
        if (l < r)
        {
            tree[2*node].lazy += tree[node].lazy;
            tree[2*node + 1].lazy += tree[node].lazy;
        }

        tree[node].lazy = 0;
    }

    void update(int l, int r, int node, int queryL, int queryR, int queryVal)
    {
        push(node, l, r);
        if (queryR < l || r < queryL)
        {
            return;
        }

        if (queryL <= l && r <= queryR)
        {
            tree[node].lazy = queryVal;
            push(node, l, r);
            return;
        }

        int mid = l + r >> 1;
        update(l, mid, 2*node, queryL, queryR, queryVal);
        update(mid + 1, r, 2*node + 1, queryL, queryR, queryVal);
        tree[node] = tree[2*node] + tree[2*node + 1];
    }

    Node query(int l, int r, int node, int queryL, int queryR)
    {
        push(node, l, r);
        if (queryL <= l && r <= queryR)
        {
            return tree[node];
        }

        Node res; res.min = INF;
        int mid = l + r >> 1;

        if (queryL <= mid) res = res + query(l, mid, 2*node, queryL, queryR);
        if (mid + 1 <= queryR) res = res + query(mid + 1, r, 2*node + 1, queryL, queryR);
        return res;
    }

    void build()
    {
        build(1, n * m, 1);
    }

    void update(int l, int r, int val)
    {
        update(1, n * m, 1, l, r, val);
    }

    int query(int l, int r)
    {
        Node res = query(1, n * m, 1, l, r);
        return res.cnt;
    }
};

SegmentTreeLazy tree;
std::vector <int> t[MAXN];
std::vector <int> row, col;

void add(int idx)
{
    tree.update(std::min(t[1][idx], t[1][idx - 1]), std::max(t[1][idx], t[1][idx - 1]) - 1, 1);
}

void rem(int idx)
{
    tree.update(std::min(t[1][idx], t[1][idx - 1]), std::max(t[1][idx], t[1][idx - 1]) - 1, -1);
}

void give_initial_chart(int H, int W, std::vector<int> R, std::vector<int> C)
{
    n = H;
    m = W;
    for (int i = 1 ; i <= n + 1 ; ++i)
    {
        t[i].resize(m + 2, n * m + 1);
    }

    C.insert(C.begin(), -1);
    R.insert(R.begin(), -1);
    for (int &val : R) val++;
    for (int &val : C) val++;

    row = R; col = C;
    for (int i = 1 ; i <= n * m ; ++i)
    {
        t[R[i]][C[i]] = i;
    }

    tree.build();
    for (int i = 1 ; i <= m + 1 ; ++i)
    {
        add(i);
    }
}

int swap_seats(int a, int b) 
{
    a++; b++;
    int posA = col[a];
    int posB = col[b];
    assert(t[1][posA] == a);
    assert(t[1][posB] == b);
    rem(posA);
    rem(posB);
    rem(posA + 1);
    rem(posB + 1);
    
    std::swap(t[1][posA], t[1][posB]);
    std::swap(col[a], col[b]);

    add(posA);
    add(posB);
    add(posA + 1);
    add(posB + 1);

    return tree.query(1, n * m);
}

Compilation message (stderr)

seats.cpp: In member function 'void SegmentTreeLazy::build(int, int, int)':
seats.cpp:46:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   46 |         int mid = l + r >> 1;
      |                   ~~^~~
seats.cpp: In member function 'void SegmentTreeLazy::update(int, int, int, int, int, int)':
seats.cpp:84:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   84 |         int mid = l + r >> 1;
      |                   ~~^~~
seats.cpp: In member function 'SegmentTreeLazy::Node SegmentTreeLazy::query(int, int, int, int, int)':
seats.cpp:99:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   99 |         int mid = l + r >> 1;
      |                   ~~^~~

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