Submission #197088

#	Time	Username	Problem	Language	Result	Execution time	Memory
197088		stefdasca	Dancing Elephants (IOI11_elephants)	C++14	97 / 100	9072 ms	12260 KiB

elephants

#include <bits/stdc++.h>
#include "elephants.h"

using namespace std;
int sqt = 0;
int n, L;
int V[150005];

vector<int> bucket[350];
int DP[150005];
int G[150005];
int pos[150005];
int lastbucket = 0;
int pot = 0;
vector<int> v(n);
void rebuild(bool C)
{
    pot = 0;
    if(C)
        for(int i = 0 ; i < n ; i ++)
            v.push_back(i);
    else
    {
        v.clear();
        int last = -1;
        for(int i = 0 ; i <= lastbucket; i ++)
        {
            for(int j = 0 ; j < bucket[i].size() ; j++)
            {
                v.push_back(bucket[i][j]);
                last = bucket[i][j];
            }
            bucket[i].clear();
        }
    }
    int currbucket = 0;
    for(int i = 0 ; i < n; i++)
    {
        if(bucket[currbucket].size() <= sqt)
            bucket[currbucket].push_back(v[i]);
        else
            bucket[++currbucket].push_back(v[i]);
        pos[v[i]] = currbucket;
        lastbucket = currbucket;
    }
    for(int i = 0; i <= lastbucket; i++)
    {
        int curr = 0;
        int X = bucket[i].size();
        curr = X-1;
        for(int j = X - 1; j >= 0; j--)
        {
            DP[bucket[i][j]] = 1;
            while(curr > j && V[bucket[i][curr - 1]] > (V[bucket[i][j]] + L))
                curr--;
            G[bucket[i][j]] = j;
            if(V[bucket[i][curr]] > (V[bucket[i][j]] + L))
            {
                DP[bucket[i][j]] += DP[bucket[i][curr]];
                G[bucket[i][j]] = G[bucket[i][curr]];
            }
        }
    }
}

void erase_elem(int currbucket, int vl)
{
    vector<int> w;
    for(int i = 0; i < bucket[currbucket].size(); i++)
    {
        if(bucket[currbucket][i] == vl)
            continue;
        w.push_back(bucket[currbucket][i]);
    }
    bucket[currbucket] = w;
    int i = currbucket;
    int X = bucket[i].size();
    int curr = X-1;
    for(int j = X - 1; j >= 0; j--)
    {
        DP[bucket[i][j]] = 1;
        while(curr > j && V[bucket[i][curr - 1]] > (V[bucket[i][j]] + L))
            curr--;
        G[bucket[i][j]] = j;
        if(V[bucket[i][curr]] > (V[bucket[i][j]] + L))
        {
            DP[bucket[i][j]] += DP[bucket[i][curr]];
            G[bucket[i][j]] = G[bucket[i][curr]];
        }
    }
}

void add_elem(int currbucket, int vl)
{
    vector<int> w;
    bool gone = 0;
    pos[vl] = currbucket;
    for(int i = 0; i < bucket[currbucket].size(); i++)
    {
        if(V[bucket[currbucket][i]] >= V[vl] && !gone)
        {
            gone = 1;
            w.push_back(vl);
        }
        w.push_back(bucket[currbucket][i]);
    }
    if(!gone)
        w.push_back(vl);
    swap(bucket[currbucket], w);
    int i = currbucket;
    int X = bucket[i].size();
    int curr = X - 1;
    for(int j = X - 1; j >= 0; j--)
    {
        DP[bucket[i][j]] = 1;
        while(curr > j && V[bucket[i][curr - 1]] > (V[bucket[i][j]] + L))
            curr--;
        G[bucket[i][j]] = j;
        if(V[bucket[i][curr]] > (V[bucket[i][j]] + L))
        {
            DP[bucket[i][j]] += DP[bucket[i][curr]];
            G[bucket[i][j]] = G[bucket[i][curr]];
        }
    }
}

void init(int N, int Lx, int X[])
{
    sqt = 850;
    n = N;
    L = Lx;
    for(int i = 0; i < N ; i++)
        V[i] = X[i];
    rebuild(1);
}

int update(int ix, int yx)
{
    erase_elem(pos[ix],ix);
    int oldd = pos[ix];
    V[ix] = yx;
    int newbucket = lastbucket;
    for(int i = 0; i < lastbucket; i++)
        if(bucket[i+1].size() && V[bucket[i+1].front()] >= yx)
        {
            newbucket = i;
            break;
        }
    add_elem(newbucket, ix);
    pot++;
    if(bucket[oldd].size() == 0 || pot >= sqt)
        rebuild(0);
    int currpos = 0;
    int currbucket = 0;
    int ans = 0;
    while(1)
    {
        ans += DP[bucket[currbucket][currpos]];
        currpos = G[bucket[currbucket][currpos]];
        int ansj = -1;
        int R = V[bucket[currbucket][currpos]] + L;
        for(int j = currbucket + 1 ; j <= lastbucket ; j++)
        {
            if(V[bucket[j].back()] <= R)
                continue;
            else
            {
                ansj = j;
                break;
            }
        }
        if(ansj == -1)
            break;
        else
        {
            currbucket = ansj;
            int l= 0, r = bucket[currbucket].size();
            r--;
            int ansj2 = -1;
            while(l <= r)
            {
                int mid = (l+r)/2;
                if(V[bucket[ansj][mid]] > R)
                {
                    r = mid - 1;
                    ansj2 = mid;
                }
                else
                    l = mid + 1;
            }
            currpos = ansj2;
        }
    }
    return ans;

}

Compilation message (stderr)

elephants.cpp: In function 'void rebuild(bool)':
elephants.cpp:28:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for(int j = 0 ; j < bucket[i].size() ; j++)
                             ~~^~~~~~~~~~~~~~~~~~
elephants.cpp:25:13: warning: variable 'last' set but not used [-Wunused-but-set-variable]
         int last = -1;
             ^~~~
elephants.cpp:39:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if(bucket[currbucket].size() <= sqt)
            ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
elephants.cpp: In function 'void erase_elem(int, int)':
elephants.cpp:69:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < bucket[currbucket].size(); i++)
                    ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
elephants.cpp: In function 'void add_elem(int, int)':
elephants.cpp:98:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < bucket[currbucket].size(); i++)
                    ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 16 / 16
• Subtask 3: 24 / 24
• Subtask 4: 47 / 47
• Subtask 5: 0 / 3