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Submission #45015

# Submission time Handle Problem Language Result Execution time Memory
45015 2018-04-10T14:52:53 Z SpaimaCarpatilor Candies (JOI18_candies) C++17
100 / 100
 310 ms 13100 KB 
#include<bits/stdc++.h>

using namespace std;

int N, a[200009], t[200009], id[200009], lft[200009], rgt[200009], isActive[200009];
long long s[200009];
bool canTake[200009], taken[200009];
set < pair < long long, int > > S;

bool cmp (int i, int j)
{
    return a[i] > a[j];
}

int tata (int x)
{
    if (t[x] == x) return x;
    return t[x] = tata (t[x]);
}

long long extraP[200009];
void refresh (int root)
{
    S.erase ({extraP[root], root});
    int r = rgt[root], l = lft[root];
    if (r < N && l > 1)
    {
        long long ld = s[r] - s[l - 2], nw = s[r + 1] - (l >= 3 ? s[l - 3] : 0);
        extraP[root] = nw - ld, S.insert ({extraP[root], root});
    }
}

int main ()
{
//freopen ("input", "r", stdin);
//freopen ("output", "w", stdout);

scanf ("%d", &N);
for (int i=1; i<=N; i++)
    scanf ("%d", &a[i]), s[i] = a[i] + (i > 2 ? s[i - 2] : 0), id[i] = i, canTake[i] = 1, taken[i] = 0;
sort (id + 1, id + N + 1, cmp);
int pntr = 1;
long long ans = 0;
for (int K=1; K<=(N + 1) / 2; K++)
{
/*    printf ("%d: ", K);
    for (auto it : S)
        printf ("(%lld, %d) ", it.first, it.second);*/
    while (!S.empty () && isActive[S.rbegin ()->second] == 0)
    {
//        printf ("del (%d) ", S.rbegin ()->second);
        auto it = S.end (); it --;
        S.erase (it);
    }
//    printf ("\n");
    while (!canTake[id[pntr]] && pntr <= N) pntr ++;
    long long price1 = (pntr > N ? -1LL << 60 : (long long) a[id[pntr]]), price2 = (S.empty () ? -1LL << 60 : S.rbegin ()->first);
    if (price1 > price2)
    {
        ans += price1;
        int pos = id[pntr];
    //    printf ("add %d\n", pos);
        taken[pos] = 1, canTake[pos] = canTake[pos - 1] = canTake[pos + 1] = 0;
        if (pos >= 2 && t[pos - 2] > 0 && t[pos + 2] > 0)
        {
            int r1 = tata (t[pos - 2]), r2 = tata (t[pos + 2]);
            t[r2] = t[pos] = r1, isActive[r2] = 0;
            rgt[r1] = rgt[r2], refresh (r1);
        }
        else
        if (pos >= 2 && t[pos - 2] > 0)
        {
            int r = tata (pos - 2);
            t[pos] = r, rgt[r] = pos, refresh (r);
        }
        else
        if (t[pos + 2] > 0)
        {
            int r = tata (pos + 2);
            t[pos] = r, lft[r] = pos, refresh (r);
        }
        else t[pos] = pos, isActive[pos] = 1, lft[pos] = rgt[pos] = pos, refresh (pos);
    }
    else
    {
        ans += price2;
        int root = S.rbegin ()->second;
        //printf ("extend %d [%d, %d] -> ", root, lft[root], rgt[root]);
        lft[root] --, rgt[root] ++;
        t[lft[root]] = t[rgt[root]] = root;
        canTake[lft[root] - 1] = canTake[rgt[root] + 1] = 0;
        if (lft[root] - 2 >= 1 && t[lft[root] - 2] > 0)
        {
            int r1 = tata (lft[root] - 2);
            t[r1] = root, lft[root] = lft[r1], isActive[r1] = 0;
        }
        if (t[rgt[root] + 2] > 0)
        {
            int r2 = tata (rgt[root] + 2);
            t[r2] = root, rgt[root] = rgt[r2], isActive[r2] = 0;
        }
        //printf ("[%d %d]\n", lft[root], rgt[root]);
        refresh (root);
    }
/*    printf ("segms: ");
    set < pair < int, int > > ss;
    for (int i=1; i<=N; i++)
    if(t[i]>0)
    {
        int q=tata(i);
        ss.insert({lft[q], rgt[q]});
    }
    for(auto it:ss)
        printf("[%d, %d]",it.first, it.second);
    printf ("\n");*/
/*    for (int i=1; i<=N; i++)
        if (canTake[i]) printf ("1");
        else printf ("0");
    printf ("\n");*/
    printf ("%lld\n", ans);
}

return 0;
}

Compilation message

candies.cpp: In function 'int main()':
candies.cpp:38:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf ("%d", &N);
 ~~~~~~^~~~~~~~~~
candies.cpp:40:89: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf ("%d", &a[i]), s[i] = a[i] + (i > 2 ? s[i - 2] : 0), id[i] = i, canTake[i] = 1, taken[i] = 0;
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 504 KB Output is correct
2 Correct 3 ms 616 KB Output is correct
3 Correct 3 ms 664 KB Output is correct
4 Correct 3 ms 664 KB Output is correct
5 Correct 3 ms 664 KB Output is correct
6 Correct 3 ms 664 KB Output is correct
7 Correct 3 ms 664 KB Output is correct
8 Correct 3 ms 664 KB Output is correct
9 Correct 3 ms 712 KB Output is correct
10 Correct 3 ms 712 KB Output is correct
11 Correct 3 ms 788 KB Output is correct
12 Correct 3 ms 804 KB Output is correct
13 Correct 4 ms 804 KB Output is correct
14 Correct 3 ms 804 KB Output is correct
15 Correct 3 ms 804 KB Output is correct
16 Correct 4 ms 804 KB Output is correct
17 Correct 3 ms 804 KB Output is correct
18 Correct 3 ms 804 KB Output is correct
19 Correct 3 ms 804 KB Output is correct
20 Correct 3 ms 804 KB Output is correct

Subtask #2
92.0 / 92.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 504 KB Output is correct
2 Correct 3 ms 616 KB Output is correct
3 Correct 3 ms 664 KB Output is correct
4 Correct 3 ms 664 KB Output is correct
5 Correct 3 ms 664 KB Output is correct
6 Correct 3 ms 664 KB Output is correct
7 Correct 3 ms 664 KB Output is correct
8 Correct 3 ms 664 KB Output is correct
9 Correct 3 ms 712 KB Output is correct
10 Correct 3 ms 712 KB Output is correct
11 Correct 3 ms 788 KB Output is correct
12 Correct 3 ms 804 KB Output is correct
13 Correct 4 ms 804 KB Output is correct
14 Correct 3 ms 804 KB Output is correct
15 Correct 3 ms 804 KB Output is correct
16 Correct 4 ms 804 KB Output is correct
17 Correct 3 ms 804 KB Output is correct
18 Correct 3 ms 804 KB Output is correct
19 Correct 3 ms 804 KB Output is correct
20 Correct 3 ms 804 KB Output is correct
21 Correct 266 ms 12984 KB Output is correct
22 Correct 249 ms 12984 KB Output is correct
23 Correct 246 ms 12984 KB Output is correct
24 Correct 115 ms 12984 KB Output is correct
25 Correct 132 ms 12984 KB Output is correct
26 Correct 117 ms 12984 KB Output is correct
27 Correct 157 ms 12984 KB Output is correct
28 Correct 183 ms 12984 KB Output is correct
29 Correct 154 ms 12984 KB Output is correct
30 Correct 160 ms 12984 KB Output is correct
31 Correct 158 ms 12984 KB Output is correct
32 Correct 188 ms 12984 KB Output is correct
33 Correct 195 ms 12984 KB Output is correct
34 Correct 253 ms 13028 KB Output is correct
35 Correct 237 ms 13068 KB Output is correct
36 Correct 310 ms 13100 KB Output is correct
37 Correct 275 ms 13100 KB Output is correct
38 Correct 290 ms 13100 KB Output is correct
39 Correct 119 ms 13100 KB Output is correct
40 Correct 178 ms 13100 KB Output is correct
41 Correct 130 ms 13100 KB Output is correct
42 Correct 165 ms 13100 KB Output is correct
43 Correct 216 ms 13100 KB Output is correct
44 Correct 176 ms 13100 KB Output is correct
45 Correct 220 ms 13100 KB Output is correct
46 Correct 162 ms 13100 KB Output is correct
47 Correct 165 ms 13100 KB Output is correct
48 Correct 197 ms 13100 KB Output is correct
49 Correct 190 ms 13100 KB Output is correct
50 Correct 207 ms 13100 KB Output is correct