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Submission #40674

# Submission time Handle Problem Language Result Execution time Memory
40674 2018-02-06T18:11:17 Z bogdan10bos Boat (APIO16_boat) C++14
9 / 100
 463 ms 11940 KB 
#include <bits/stdc++.h>

using namespace std;

//#define FILE_IO

const int mod = 1e9 + 7;

int N, K;
int a[1005], b[1005], st[1005], dr[1005];
int dp[1005][4005], sum[1005][4005];  /// primele i, ultimul este in intervalul j
int fct[100005], ifct[100005], inv[100005];

class Normalize
{
public:
    map<int, int> mp;
    vector<int> ord;

    void add(int x)
    {
        if(mp.count(x)) return;
        ord.push_back(x);
        mp[x];
    }

    void normalize()
    {
        sort(ord.begin(), ord.end());
        for(int i = 0; i < ord.size(); i++)
            mp[ ord[i] ] = i;
    }

    int get(int x) { return mp[x]; }
}nrm;

int power(int x, int y)
{
    if(y <= 0)  return 1;
    int ans = power( (1LL * x * x) % mod, y >> 1 );
    if(y & 1)   ans = (1LL * x * ans) % mod;
    return ans;
}

void pre(int K)
{
    fct[0] = 1;
    for(int i = 1; i <= K; i++) fct[i] = (1LL * fct[i - 1] * i) % mod;
    ifct[K] = power(fct[K], mod - 2);
    for(int i = K - 1; i >= 0; i--) ifct[i] = (1LL * ifct[i + 1] * (i + 1)) % mod;

    for(int i = 1; i <= K; i++) inv[i] = power(i, mod - 2);
}

int C(int N, int K)
{
    if(K > N)   return 0;
    int ans = (1LL * fct[N] * ifct[K]) % mod;
    ans = (1LL * ans * ifct[N - K]) % mod;
    return ans;
}

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

    pre(1e4);

    scanf("%d", &N);
    for(int i = 1; i <= N; i++)
    {
        scanf("%d%d", &a[i], &b[i]);
        nrm.add(a[i]);
        nrm.add(b[i]);
    }
    nrm.normalize();
    for(int i = 1; i <= N; i++)
    {
        st[i] = nrm.get(a[i]);
        dr[i] = nrm.get(b[i]);
    }
    K = nrm.ord.size();

    for(int i = 0; i <= 2 * K - 1; i++) dp[0][i] = sum[0][i] = 1;

    int ans = 0;

    for(int i = 1; i <= N; i++)
    {
        sum[i][0] = sum[i - 1][0];
        for(int j = 1; j <= 2 * K - 1; j++)
        {
            dp[i][j] = dp[i][j - 1];
            if(j & 1)
            {
                int x = nrm.ord[j / 2];
                if(a[i] <= x && x <= b[i])
                    dp[i][j] = (dp[i][j] + sum[i - 1][j - 1]) % mod;
            }
            else
            {
                int lft = nrm.ord[j / 2 - 1];
                int rgt = nrm.ord[j / 2];
                int sz = rgt - lft - 1;

                if(a[i] <= lft && rgt <= b[i])
                {
                    int cnt = 0;
                    int sum = 0;
                    int c = 1;
                    for(int k = i; k > 0; k--)
                    {
                        if(a[k] <= lft && rgt <= b[k])
                        {
                            cnt++;
                            if(cnt <= sz)
                            {
                                c = (1LL * c * (sz - cnt + 1)) % mod;
                                c = (1LL * c * inv[cnt]) % mod;
                                sum = (sum + c) % mod;
                            }
                        }
                        dp[i][j] += (1LL * dp[k - 1][j - 1] * sum) % mod;
                        dp[i][j] %= mod;
                    }
                }
            }
            sum[i][j] = (sum[i - 1][j] + dp[i][j]) % mod;
        }
        ans = (ans + dp[i][2 * K - 1]) % mod;
    }
    printf("%d\n", ans);

    return 0;
}

Compilation message

boat.cpp: In member function 'void Normalize::normalize()':
boat.cpp:30:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i = 0; i < ord.size(); i++)
                          ^
boat.cpp: In function 'int main()':
boat.cpp:72:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &N);
                    ^
boat.cpp:75:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &a[i], &b[i]);
                                    ^

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 8440 KB Output is correct
2 Correct 13 ms 8440 KB Output is correct
3 Correct 15 ms 8488 KB Output is correct
4 Correct 14 ms 8688 KB Output is correct
5 Correct 14 ms 8688 KB Output is correct
6 Correct 14 ms 8688 KB Output is correct
7 Correct 14 ms 8688 KB Output is correct
8 Correct 15 ms 8688 KB Output is correct
9 Correct 14 ms 8688 KB Output is correct
10 Correct 13 ms 8688 KB Output is correct
11 Correct 13 ms 8688 KB Output is correct
12 Correct 13 ms 8688 KB Output is correct
13 Correct 14 ms 8688 KB Output is correct
14 Correct 14 ms 8688 KB Output is correct
15 Correct 13 ms 8688 KB Output is correct
16 Correct 10 ms 8688 KB Output is correct
17 Correct 9 ms 8688 KB Output is correct
18 Correct 9 ms 8688 KB Output is correct
19 Correct 9 ms 8688 KB Output is correct
20 Correct 9 ms 8688 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 8440 KB Output is correct
2 Correct 13 ms 8440 KB Output is correct
3 Correct 15 ms 8488 KB Output is correct
4 Correct 14 ms 8688 KB Output is correct
5 Correct 14 ms 8688 KB Output is correct
6 Correct 14 ms 8688 KB Output is correct
7 Correct 14 ms 8688 KB Output is correct
8 Correct 15 ms 8688 KB Output is correct
9 Correct 14 ms 8688 KB Output is correct
10 Correct 13 ms 8688 KB Output is correct
11 Correct 13 ms 8688 KB Output is correct
12 Correct 13 ms 8688 KB Output is correct
13 Correct 14 ms 8688 KB Output is correct
14 Correct 14 ms 8688 KB Output is correct
15 Correct 13 ms 8688 KB Output is correct
16 Correct 10 ms 8688 KB Output is correct
17 Correct 9 ms 8688 KB Output is correct
18 Correct 9 ms 8688 KB Output is correct
19 Correct 9 ms 8688 KB Output is correct
20 Correct 9 ms 8688 KB Output is correct
21 Incorrect 463 ms 11940 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 10 ms 11940 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 8440 KB Output is correct
2 Correct 13 ms 8440 KB Output is correct
3 Correct 15 ms 8488 KB Output is correct
4 Correct 14 ms 8688 KB Output is correct
5 Correct 14 ms 8688 KB Output is correct
6 Correct 14 ms 8688 KB Output is correct
7 Correct 14 ms 8688 KB Output is correct
8 Correct 15 ms 8688 KB Output is correct
9 Correct 14 ms 8688 KB Output is correct
10 Correct 13 ms 8688 KB Output is correct
11 Correct 13 ms 8688 KB Output is correct
12 Correct 13 ms 8688 KB Output is correct
13 Correct 14 ms 8688 KB Output is correct
14 Correct 14 ms 8688 KB Output is correct
15 Correct 13 ms 8688 KB Output is correct
16 Correct 10 ms 8688 KB Output is correct
17 Correct 9 ms 8688 KB Output is correct
18 Correct 9 ms 8688 KB Output is correct
19 Correct 9 ms 8688 KB Output is correct
20 Correct 9 ms 8688 KB Output is correct
21 Incorrect 463 ms 11940 KB Output isn't correct
22 Halted 0 ms 0 KB -