Submission #772215

#	Time	Username	Problem	Language	Result	Execution time	Memory
772215		danikoynov	Potatoes and fertilizers (LMIO19_bulves)	C++14	30 / 100	178 ms	36420 KiB

bulves

#include <iostream>
#include <set> 
#include <cassert>
#include <numeric>
#define endl '\n'
 
typedef long long ll;

const int BUFF_SIZE = 1e6;
int buffPos = BUFF_SIZE - 1;
char buff[BUFF_SIZE];

void readChar()
{
    if (++buffPos == BUFF_SIZE) fread(buff, BUFF_SIZE, 1, stdin), buffPos = 0;
}

void readInt(int &num)
{
    num = 0;
    for (; '0' > buff[buffPos] || buff[buffPos] > '9' ; readChar());
    for (; '0' <= buff[buffPos] && buff[buffPos] <= '9' ; readChar())
        num = 10 * num + buff[buffPos] - '0';
}

struct slope_trick
{
    const ll inf = 1e18;
 
    std::multiset < ll > left_set, right_set;
    ll height;
 
    slope_trick()
    {
        height = 0;
    }
 
    void add_basic(ll v) /// adds |x - v|
    {
        ll left = -inf;
        ll right = inf;
        if (!left_set.empty())
            left = *left_set.rbegin();
        if (!right_set.empty())
            right = *right_set.begin();
 
 
        if (v >= left && v <= right) /// function on base
        {
            left_set.insert(v);
            right_set.insert(v);
        }
        else
        if (v < left)
        {
                left_set.erase(left_set.find(left));
            right_set.insert(left);
 
            left_set.insert(v);
            left_set.insert(v);
            
            height = height + abs(left - v);
        }
        else
        if (v > right)
        {
            ///std::cout << v << " " << right << endl; 
   
                right_set.erase(right_set.begin());
            left_set.insert(right);
 
            right_set.insert(v);
            right_set.insert(v);
 
            height = height + abs(right - v);
        }
    }
 
 
    void print_slope_trick()
    {
        std::cout << "left_slope" << endl;
        for (int cor : left_set)
            std::cout << cor << " ";
            std::cout << endl;
            std::cout << "right_slope" << endl;
        for (int cor : right_set)
            std::cout << cor << " ";
        std::cout << endl;
        std::cout << "height " << height << endl;
    }
 
    ll get_right()
    {
        if (right_set.empty())
            return inf;
        return *right_set.begin();
    }
 
    ll get_left()
    {
        if (left_set.empty())
            return -inf;
        return *left_set.rbegin();
    }
 
    void prefix_minimum()
    {
        while(left_set.size() > 0)
        {       
            ll val = *left_set.begin();
            if (val >= 0)
                break;
                assert(left_set.size() > 0);
            left_set.erase(left_set.find(val));
        }
 
        ll slope = 0, base = height, last = get_right();
        
        while (get_right() <= 0)
        {
            ll distance = get_right() - last;
            base = base + distance * slope;
            slope ++;
            last = last + distance;
            assert(right_set.size() > 0);
            right_set.erase(right_set.begin());
        }
        
        if (slope != 0)
        {
            base = base + (- last) * slope;
            right_set.insert(0);
        }
        height = base;
 
        right_set.clear();
        ///right_set.clear();
    }
 
    ll query_vlaue(ll debit)
    {   
        ll last = get_left(), slope = 0, base = height;
        while(left_set.size() > 0 && last > debit)
        {
            ll distance = last - get_left();
            base = base + distance * slope;
            slope ++;
            last = last - distance;
            assert(left_set.size() > 0);
            left_set.erase(left_set.find(*left_set.rbegin()));
        }

        if (slope != 0)
        {
            base = base + (last - debit) * slope;
        }
 
        return base;
    }
};
 
 
const int maxn = 500010;
 
int n;
int a[maxn], b[maxn];
ll x[maxn], pref[maxn];
 
void solve()
{
    readInt(n);
    for (int i = 1; i <= n; i ++)
    {
        readInt(a[i]);
        readInt(b[i]);
        x[i] = a[i] - b[i];
        pref[i] = pref[i - 1] + x[i];
    }
 
    slope_trick st;
    for (int i = 1; i <= n; i ++)
    {
        st.add_basic(pref[i]);
        st.prefix_minimum();
        //std::cout << "--------------------" << endl;
        //st.print_slope_trick();
    }
    ///std::cout << "dasdas" << endl;
    ll ans = st.query_vlaue(pref[n]);
    ///std::cout << "-----------------" << endl;
    std::cout << ans << endl;
}
 
void speed()
{
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(NULL);
    std::cout.tie(NULL);
}
 
int main()
{
    speed();
    solve();
    return 0;
}

Compilation message (stderr)

bulves.cpp: In member function 'void slope_trick::print_slope_trick()':
bulves.cpp:83:9: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   83 |         for (int cor : left_set)
      |         ^~~
bulves.cpp:85:13: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   85 |             std::cout << endl;
      |             ^~~
bulves.cpp: In function 'void readChar()':
bulves.cpp:15:38: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |     if (++buffPos == BUFF_SIZE) fread(buff, BUFF_SIZE, 1, stdin), buffPos = 0;
      |                                 ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 24
• Subtask 2: 0 / 10
• Subtask 3: 20 / 20
• Subtask 4: 10 / 10
• Subtask 5: 0 / 36