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Submission #109548

# Submission time Handle Problem Language Result Execution time Memory
109548 2019-05-07T03:58:27 Z PeppaPig Boat (APIO16_boat) C++14
36 / 100
 2000 ms 4428 KB 
#include <bits/stdc++.h>

#define long long long

using namespace std;

const int N = 1005;
const int M = 1e9+7;

long fac[N], inv[N];

long modpow(long a, long b) {
    long ret = 1;
    for( ; b; b >>= 1) {
        if(b & 1) ret = (ret * a) % M;
        a = (a * a) % M;
    }
    return ret;
}

void pre_process() {
    fac[0] = inv[0] = 1;
    for(int i = 1; i < N; i++) fac[i] = (fac[i-1] * i) % M;
    for(int i = 1; i < N; i++) inv[i] = modpow(fac[i], M-2);
}

long ncr(int n, int r) { return fac[n] * (inv[r] * inv[n-r] % M) % M; }

int n, a[N], b[N];
long dp[N][N];
vector<int> coord;

int main() {
    pre_process();
    scanf("%d", &n);
    for(int i = 1; i <= n; i++) {
        scanf("%d %d", a+i, b+i);
        coord.emplace_back(a[i]);
        coord.emplace_back(++b[i]);
    }
    sort(coord.begin(), coord.end());
    coord.resize(unique(coord.begin(), coord.end()) - coord.begin());
    for(int i = 1; i <= n; i++) {
        a[i] = lower_bound(coord.begin(), coord.end(), a[i]) - coord.begin() + 1;
        b[i] = lower_bound(coord.begin(), coord.end(), b[i]) - coord.begin() + 1;
    }
    for(int i = 0; i < coord.size(); i++) dp[0][i] = 1;
    for(int i = 1; i <= n; i++) {
        for(int j = a[i]; j < b[i]; j++) {
            long p = coord[j] - coord[j-1], cnt = 1;
            for(int k = i-1; ~k; k--) {
                dp[i][j] = (dp[i][j] + (p * dp[k][j-1]) % M) % M;
                if(a[k] <= j && j < b[k]) {
                    ++cnt;
                    p = (p * (coord[j] - coord[j-1] + cnt - 1)) % M;
                    p = (p * modpow(cnt, M-2)) % M;
                }
            }
        }
        for(int j = 1; j < coord.size(); j++) dp[i][j] = (dp[i][j] + dp[i][j-1]) % M;
    }
    long ans = 0;
    for(int i = 1; i <= n; i++) ans = (ans + dp[i][coord.size()-1]) % M;
    printf("%lld\n", ans);

    return 0;
}

Compilation message

boat.cpp: In function 'int main()':
boat.cpp:47:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < coord.size(); i++) dp[0][i] = 1;
                    ~~^~~~~~~~~~~~~~
boat.cpp:60:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j = 1; j < coord.size(); j++) dp[i][j] = (dp[i][j] + dp[i][j-1]) % M;
                        ~~^~~~~~~~~~~~~~
boat.cpp:35:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
boat.cpp:37:14: 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 12 ms 4352 KB Output is correct
2 Correct 11 ms 4224 KB Output is correct
3 Correct 11 ms 4224 KB Output is correct
4 Correct 12 ms 4224 KB Output is correct
5 Correct 13 ms 4428 KB Output is correct
6 Correct 12 ms 4224 KB Output is correct
7 Correct 13 ms 4352 KB Output is correct
8 Correct 11 ms 4352 KB Output is correct
9 Correct 11 ms 4224 KB Output is correct
10 Correct 12 ms 4224 KB Output is correct
11 Correct 12 ms 4244 KB Output is correct
12 Correct 15 ms 4224 KB Output is correct
13 Correct 13 ms 4352 KB Output is correct
14 Correct 16 ms 4352 KB Output is correct
15 Correct 12 ms 4352 KB Output is correct
16 Correct 8 ms 3072 KB Output is correct
17 Correct 7 ms 3072 KB Output is correct
18 Correct 9 ms 3072 KB Output is correct
19 Correct 9 ms 3072 KB Output is correct
20 Correct 8 ms 3072 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 4352 KB Output is correct
2 Correct 11 ms 4224 KB Output is correct
3 Correct 11 ms 4224 KB Output is correct
4 Correct 12 ms 4224 KB Output is correct
5 Correct 13 ms 4428 KB Output is correct
6 Correct 12 ms 4224 KB Output is correct
7 Correct 13 ms 4352 KB Output is correct
8 Correct 11 ms 4352 KB Output is correct
9 Correct 11 ms 4224 KB Output is correct
10 Correct 12 ms 4224 KB Output is correct
11 Correct 12 ms 4244 KB Output is correct
12 Correct 15 ms 4224 KB Output is correct
13 Correct 13 ms 4352 KB Output is correct
14 Correct 16 ms 4352 KB Output is correct
15 Correct 12 ms 4352 KB Output is correct
16 Correct 8 ms 3072 KB Output is correct
17 Correct 7 ms 3072 KB Output is correct
18 Correct 9 ms 3072 KB Output is correct
19 Correct 9 ms 3072 KB Output is correct
20 Correct 8 ms 3072 KB Output is correct
21 Execution timed out 2033 ms 3772 KB Time limit exceeded
22 Halted 0 ms 0 KB -

Subtask #3
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 896 KB Output is correct
2 Correct 19 ms 900 KB Output is correct
3 Correct 23 ms 896 KB Output is correct
4 Correct 25 ms 888 KB Output is correct
5 Correct 31 ms 896 KB Output is correct
6 Correct 52 ms 888 KB Output is correct
7 Correct 57 ms 896 KB Output is correct
8 Correct 53 ms 900 KB Output is correct
9 Correct 58 ms 1016 KB Output is correct
10 Correct 52 ms 888 KB Output is correct
11 Correct 31 ms 888 KB Output is correct
12 Correct 19 ms 1024 KB Output is correct
13 Correct 23 ms 896 KB Output is correct
14 Correct 23 ms 888 KB Output is correct
15 Correct 29 ms 896 KB Output is correct
16 Correct 16 ms 768 KB Output is correct
17 Correct 16 ms 892 KB Output is correct
18 Correct 16 ms 896 KB Output is correct
19 Correct 14 ms 768 KB Output is correct
20 Correct 17 ms 768 KB Output is correct

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 4352 KB Output is correct
2 Correct 11 ms 4224 KB Output is correct
3 Correct 11 ms 4224 KB Output is correct
4 Correct 12 ms 4224 KB Output is correct
5 Correct 13 ms 4428 KB Output is correct
6 Correct 12 ms 4224 KB Output is correct
7 Correct 13 ms 4352 KB Output is correct
8 Correct 11 ms 4352 KB Output is correct
9 Correct 11 ms 4224 KB Output is correct
10 Correct 12 ms 4224 KB Output is correct
11 Correct 12 ms 4244 KB Output is correct
12 Correct 15 ms 4224 KB Output is correct
13 Correct 13 ms 4352 KB Output is correct
14 Correct 16 ms 4352 KB Output is correct
15 Correct 12 ms 4352 KB Output is correct
16 Correct 8 ms 3072 KB Output is correct
17 Correct 7 ms 3072 KB Output is correct
18 Correct 9 ms 3072 KB Output is correct
19 Correct 9 ms 3072 KB Output is correct
20 Correct 8 ms 3072 KB Output is correct
21 Execution timed out 2033 ms 3772 KB Time limit exceeded
22 Halted 0 ms 0 KB -