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Submission #40727

# Submission time Handle Problem Language Result Execution time Memory
40727 2018-02-07T14:23:23 Z bogdan10bos Skyscraper (JOI16_skyscraper) C++14
100 / 100
 146 ms 18720 KB 
#include <bits/stdc++.h>

using namespace std;

//#define FILE_IO

const int mod = 1e9 + 7;

typedef pair<int, int> pii;
typedef pair<pii, pii> p4i;

int N, L;
int v[105];
int dp[105][105][1005][3];
bool inq[105][105][1005][3];
/// dp[i][j][k][e] - first i numbers, j remaining gaps, k cost, e ends are fixed
queue<p4i> q;

void addto(int x, int y, int z, int e, int vl)
{
    if(x == 3 && y == 1 && z == 4 && e == 1)
    {
        x++;
        x--;
    }

    if(x < 0 || y < 0 || z < 0 || e < 0)    return;
    if(z > L)   return;
    if(vl == 0) return;
    if(y == 1 && e == 0)    return;
    if(y == 0 && e <= 1)    return;
    if(x != N && y == 0)    return;
    if(y > N - x)
        return;

    dp[x][y][z][e] += vl;
    if(dp[x][y][z][e] >= mod)   dp[x][y][z][e] -= mod;
    if(!inq[x][y][z][e])
    {
        q.push( { {x, y}, {z, e} } );
        inq[x][y][z][e] = 1;
    }
}

void brute(int v[])
{
    vector<int> p;
    for(int i = 1; i <= N; i++) p.push_back(v[i]);
    vector< vector<int> > pp[105];

    sort(p.begin(), p.end());

    int ans = 0;
    do
    {
        int cnt = 0;
        for(int i = 1; i < p.size(); i++)
            cnt += abs(p[i] - p[i - 1]);
        if(cnt <= L)    ans++;
    }while(next_permutation(p.begin(), p.end()));
    printf("%d\n", ans);
}

int main()
{
    #ifdef FILE_IO
    freopen("1.in", "r", stdin);
    freopen("1.out", "w", stdout);
    #endif

    scanf("%d%d", &N, &L);
    for(int i = 1; i <= N; i++) scanf("%d", &v[i]);
    sort(v + 1, v + N + 1);

    if(N <= 8)
    {
        brute(v);
        exit(0);
    }

    dp[1][2][0][0] = 1; q.push({ {1, 2}, {0, 0} });
    dp[1][1][0][1] = 2; q.push({ {1, 1}, {0, 1} });

    int ans = 0;
    while(!q.empty())
    {
        auto x = q.front();
        q.pop();

        int i = x.first.first;
        int j = x.first.second;
        int k = x.second.first;
        int e = x.second.second;

        int nk = k + (v[i + 1] - v[i]) * (2 * j - 2 + e);
        int vl = dp[i][j][k][e];

        if(nk > L)  continue;

        if(i == N)
        {
            if(j == 0 && e == 2 && k <= L)
                (ans += dp[i][j][k][e]) %= mod;
            continue;
        }

        /// middle, no fix
        addto(i + 1, j + 1, nk, e, (1LL * vl * j) % mod);
        /// middle, 1 fix, 1 free
        addto(i + 1, j, nk, e, (1LL * vl * (j * 2 - 2 + e)) % mod);
        /// middle, 2 fix
        addto(i + 1, j - 1, nk, e, (1LL * vl * (j - 2 + e)) % mod);

        if(e == 0)
        {
            /// end, no fix
            addto(i + 1, j, nk, e + 1, (2 * vl) % mod);
            /// end, fix
            addto(i + 1, j - 1, nk, e + 1, (2 * vl) % mod);
        }
        else if(e == 1)
        {
            /// end, no fix
            addto(i + 1, j, nk, e + 1, vl);
            /// end, fix
            addto(i + 1, j - 1, nk, e + 1, vl);
        }
    }

    printf("%d\n", ans);

    return 0;
}

Compilation message

skyscraper.cpp: In function 'void brute(int*)':
skyscraper.cpp:57:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i = 1; i < p.size(); i++)
                          ^
skyscraper.cpp: In function 'int main()':
skyscraper.cpp:71:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &N, &L);
                          ^
skyscraper.cpp:72:51: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for(int i = 1; i <= N; i++) scanf("%d", &v[i]);
                                                   ^

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 248 KB Output is correct
2 Correct 2 ms 352 KB Output is correct
3 Correct 2 ms 588 KB Output is correct
4 Correct 2 ms 588 KB Output is correct
5 Correct 2 ms 588 KB Output is correct
6 Correct 2 ms 588 KB Output is correct
7 Correct 2 ms 588 KB Output is correct
8 Correct 2 ms 592 KB Output is correct
9 Correct 2 ms 592 KB Output is correct
10 Correct 2 ms 728 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 904 KB Output is correct
2 Correct 2 ms 1032 KB Output is correct
3 Correct 2 ms 1160 KB Output is correct
4 Correct 2 ms 1160 KB Output is correct
5 Correct 2 ms 1160 KB Output is correct
6 Correct 2 ms 1164 KB Output is correct
7 Correct 2 ms 1164 KB Output is correct
8 Correct 2 ms 1164 KB Output is correct
9 Correct 2 ms 1164 KB Output is correct
10 Correct 2 ms 1164 KB Output is correct

Subtask #3
80.0 / 80.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 248 KB Output is correct
2 Correct 2 ms 352 KB Output is correct
3 Correct 2 ms 588 KB Output is correct
4 Correct 2 ms 588 KB Output is correct
5 Correct 2 ms 588 KB Output is correct
6 Correct 2 ms 588 KB Output is correct
7 Correct 2 ms 588 KB Output is correct
8 Correct 2 ms 592 KB Output is correct
9 Correct 2 ms 592 KB Output is correct
10 Correct 2 ms 728 KB Output is correct
11 Correct 2 ms 904 KB Output is correct
12 Correct 2 ms 1032 KB Output is correct
13 Correct 2 ms 1160 KB Output is correct
14 Correct 2 ms 1160 KB Output is correct
15 Correct 2 ms 1160 KB Output is correct
16 Correct 2 ms 1164 KB Output is correct
17 Correct 2 ms 1164 KB Output is correct
18 Correct 2 ms 1164 KB Output is correct
19 Correct 2 ms 1164 KB Output is correct
20 Correct 2 ms 1164 KB Output is correct
21 Correct 4 ms 2212 KB Output is correct
22 Correct 146 ms 18720 KB Output is correct
23 Correct 40 ms 18720 KB Output is correct
24 Correct 63 ms 18720 KB Output is correct
25 Correct 49 ms 18720 KB Output is correct
26 Correct 42 ms 18720 KB Output is correct
27 Correct 40 ms 18720 KB Output is correct
28 Correct 54 ms 18720 KB Output is correct
29 Correct 95 ms 18720 KB Output is correct
30 Correct 49 ms 18720 KB Output is correct