oj.uz

Submission #163331

# Submission time Handle Problem Language Result Execution time Memory
163331 2019-11-12T16:58:27 Z Akashi Boat (APIO16_boat) C++14
9 / 100
 342 ms 11000 KB 
#include <bits/stdc++.h>
using namespace std;

const int MOD = 1e9 + 7;

struct interv{
    int x, y;
};
interv a[501];

int n, sz;
int dif[2001];
int inv_mod[2001];
int d[501][2001];
int C[2001][2001];
vector <int> v;

int lgput(int x, int p){
    int aux = x, ans = 1;
    for(int i = 1; i <= p ; i = i << 1){
        if(i & p) ans = (1LL * ans * aux) % MOD;
        aux = (1LL * aux * aux) % MOD;
    }
    return ans;
}

void calc_comb(int lin, int n, int k){
    int prod = 1;
    C[lin][0] = 1;
    for(int i = 1; i <= k ; ++i){
        prod = (1LL * prod * (n - i + 1)) % MOD;
        prod = (1LL * prod * inv_mod[i]) % MOD;
        C[lin][i] = prod;
    }
}

void prec(){
    for(int i = 1; i <= n ; ++i)
        inv_mod[i] = lgput(i, MOD - 2);

    for(int k = 2; k <= sz ; ++k)
        calc_comb(k, dif[k], min(n, dif[k]));
}

int main()
{
//    freopen("1.in", "r", stdin);

    scanf("%d", &n);
    for(int i = 1; i <= n ; ++i){
        scanf("%d%d", &a[i].x, &a[i].y);
        v.push_back(a[i].x);
        v.push_back(a[i].x - 1);
        v.push_back(a[i].y);
        v.push_back(a[i].y - 1);
    }

    sort(v.begin(), v.end());
    v.erase(unique(v.begin(), v.end()), v.end());

    sz = v.size();
    for(int i = 2; i <= sz ; ++i) dif[i] = v[i - 1] - v[i - 2];

    for(int i = 1; i <= n ; ++i){
        a[i].x = lower_bound(v.begin(), v.end(), a[i].x) - v.begin() + 1;
        a[i].y = lower_bound(v.begin(), v.end(), a[i].y) - v.begin() + 1;
    }

    prec();

    for(int j = 0; j <= sz ; ++j) d[0][j] = 1;
    for(int j = a[1].x; j <= a[1].y ; ++j) d[1][j] = dif[j];

    d[1][0] += 1;
    for(int j = 1; j <= sz ; ++j){
        d[1][j] += d[1][j - 1];
        if(d[1][j] >= MOD) d[1][j] -= MOD;
    }

    for(int i = 2; i <= n ; ++i){
        for(int j = a[i].x; j <= a[i].y ; ++j){
            for(int k = 1; k <= i ; ++k){
                if((a[k].y < j || a[k].x > j) || dif[j] < i - k + 1) continue ;

                d[i][j] = d[i][j] + (1LL * d[k - 1][j - 1] * C[j][i - k + 1]) % MOD;
                if(d[i][j] >= MOD) d[i][j] -= MOD;
            }
        }

        for(int j = 1; j <= sz ; ++j){
            d[i][j] += d[i][j - 1];
            if(d[i][j] >= MOD) d[i][j] -= MOD;
        }

        for(int j = 0; j <= sz ; ++j){
            d[i][j] += d[i - 1][j];
            if(d[i][j] >= MOD) d[i][j] -= MOD;
        }
    }

    --d[n][sz];
    if(d[n][sz] < 0) d[n][sz] += MOD;
    printf("%d", d[n][sz]);

    return 0;
}

Compilation message

boat.cpp: In function 'int main()':
boat.cpp:49:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
boat.cpp:51:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &a[i].x, &a[i].y);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 31 ms 9208 KB Output is correct
2 Correct 17 ms 9336 KB Output is correct
3 Correct 17 ms 9208 KB Output is correct
4 Correct 18 ms 9336 KB Output is correct
5 Correct 17 ms 9212 KB Output is correct
6 Correct 18 ms 9208 KB Output is correct
7 Correct 17 ms 9336 KB Output is correct
8 Correct 17 ms 9208 KB Output is correct
9 Correct 17 ms 9336 KB Output is correct
10 Correct 16 ms 9208 KB Output is correct
11 Correct 19 ms 9336 KB Output is correct
12 Correct 17 ms 9336 KB Output is correct
13 Correct 18 ms 9208 KB Output is correct
14 Correct 17 ms 9336 KB Output is correct
15 Correct 17 ms 9336 KB Output is correct
16 Correct 8 ms 3576 KB Output is correct
17 Correct 7 ms 3704 KB Output is correct
18 Correct 8 ms 3704 KB Output is correct
19 Correct 8 ms 3676 KB Output is correct
20 Correct 7 ms 3704 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 31 ms 9208 KB Output is correct
2 Correct 17 ms 9336 KB Output is correct
3 Correct 17 ms 9208 KB Output is correct
4 Correct 18 ms 9336 KB Output is correct
5 Correct 17 ms 9212 KB Output is correct
6 Correct 18 ms 9208 KB Output is correct
7 Correct 17 ms 9336 KB Output is correct
8 Correct 17 ms 9208 KB Output is correct
9 Correct 17 ms 9336 KB Output is correct
10 Correct 16 ms 9208 KB Output is correct
11 Correct 19 ms 9336 KB Output is correct
12 Correct 17 ms 9336 KB Output is correct
13 Correct 18 ms 9208 KB Output is correct
14 Correct 17 ms 9336 KB Output is correct
15 Correct 17 ms 9336 KB Output is correct
16 Correct 8 ms 3576 KB Output is correct
17 Correct 7 ms 3704 KB Output is correct
18 Correct 8 ms 3704 KB Output is correct
19 Correct 8 ms 3676 KB Output is correct
20 Correct 7 ms 3704 KB Output is correct
21 Incorrect 342 ms 11000 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 7 ms 2552 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 31 ms 9208 KB Output is correct
2 Correct 17 ms 9336 KB Output is correct
3 Correct 17 ms 9208 KB Output is correct
4 Correct 18 ms 9336 KB Output is correct
5 Correct 17 ms 9212 KB Output is correct
6 Correct 18 ms 9208 KB Output is correct
7 Correct 17 ms 9336 KB Output is correct
8 Correct 17 ms 9208 KB Output is correct
9 Correct 17 ms 9336 KB Output is correct
10 Correct 16 ms 9208 KB Output is correct
11 Correct 19 ms 9336 KB Output is correct
12 Correct 17 ms 9336 KB Output is correct
13 Correct 18 ms 9208 KB Output is correct
14 Correct 17 ms 9336 KB Output is correct
15 Correct 17 ms 9336 KB Output is correct
16 Correct 8 ms 3576 KB Output is correct
17 Correct 7 ms 3704 KB Output is correct
18 Correct 8 ms 3704 KB Output is correct
19 Correct 8 ms 3676 KB Output is correct
20 Correct 7 ms 3704 KB Output is correct
21 Incorrect 342 ms 11000 KB Output isn't correct
22 Halted 0 ms 0 KB -