oj.uz

Submission #163328

# Submission time Handle Problem Language Result Execution time Memory
163328 2019-11-12T16:53:24 Z Akashi Boat (APIO16_boat) C++14
9 / 100
 268 ms 11000 KB 
#include <bits/stdc++.h>
using namespace std;

const int MOD = 1e9 + 7;

struct interv{
    int x, y;
    bool operator < (const interv &aux)const{
        if(y != aux.y) return y < aux.y;
        return x < aux.x;
    }
};
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 || 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:53:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
boat.cpp:55:14: 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 17 ms 9336 KB Output is correct
2 Correct 17 ms 9336 KB Output is correct
3 Correct 17 ms 9208 KB Output is correct
4 Correct 17 ms 9208 KB Output is correct
5 Correct 17 ms 9208 KB Output is correct
6 Correct 16 ms 9336 KB Output is correct
7 Correct 16 ms 9264 KB Output is correct
8 Correct 17 ms 9336 KB Output is correct
9 Correct 16 ms 9208 KB Output is correct
10 Correct 16 ms 9208 KB Output is correct
11 Correct 16 ms 9208 KB Output is correct
12 Correct 17 ms 9208 KB Output is correct
13 Correct 16 ms 9208 KB Output is correct
14 Correct 16 ms 9208 KB Output is correct
15 Correct 16 ms 9208 KB Output is correct
16 Correct 7 ms 3576 KB Output is correct
17 Correct 7 ms 3644 KB Output is correct
18 Correct 7 ms 3576 KB Output is correct
19 Correct 7 ms 3704 KB Output is correct
20 Correct 7 ms 3616 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 9336 KB Output is correct
2 Correct 17 ms 9336 KB Output is correct
3 Correct 17 ms 9208 KB Output is correct
4 Correct 17 ms 9208 KB Output is correct
5 Correct 17 ms 9208 KB Output is correct
6 Correct 16 ms 9336 KB Output is correct
7 Correct 16 ms 9264 KB Output is correct
8 Correct 17 ms 9336 KB Output is correct
9 Correct 16 ms 9208 KB Output is correct
10 Correct 16 ms 9208 KB Output is correct
11 Correct 16 ms 9208 KB Output is correct
12 Correct 17 ms 9208 KB Output is correct
13 Correct 16 ms 9208 KB Output is correct
14 Correct 16 ms 9208 KB Output is correct
15 Correct 16 ms 9208 KB Output is correct
16 Correct 7 ms 3576 KB Output is correct
17 Correct 7 ms 3644 KB Output is correct
18 Correct 7 ms 3576 KB Output is correct
19 Correct 7 ms 3704 KB Output is correct
20 Correct 7 ms 3616 KB Output is correct
21 Incorrect 268 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 2548 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 9336 KB Output is correct
2 Correct 17 ms 9336 KB Output is correct
3 Correct 17 ms 9208 KB Output is correct
4 Correct 17 ms 9208 KB Output is correct
5 Correct 17 ms 9208 KB Output is correct
6 Correct 16 ms 9336 KB Output is correct
7 Correct 16 ms 9264 KB Output is correct
8 Correct 17 ms 9336 KB Output is correct
9 Correct 16 ms 9208 KB Output is correct
10 Correct 16 ms 9208 KB Output is correct
11 Correct 16 ms 9208 KB Output is correct
12 Correct 17 ms 9208 KB Output is correct
13 Correct 16 ms 9208 KB Output is correct
14 Correct 16 ms 9208 KB Output is correct
15 Correct 16 ms 9208 KB Output is correct
16 Correct 7 ms 3576 KB Output is correct
17 Correct 7 ms 3644 KB Output is correct
18 Correct 7 ms 3576 KB Output is correct
19 Correct 7 ms 3704 KB Output is correct
20 Correct 7 ms 3616 KB Output is correct
21 Incorrect 268 ms 11000 KB Output isn't correct
22 Halted 0 ms 0 KB -