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Submission #315993

# Submission time Handle Problem Language Result Execution time Memory
315993 2020-10-24T17:20:24 Z phathnv Boat (APIO16_boat) C++11
100 / 100
 1553 ms 6392 KB 
#include <bits/stdc++.h>

#define mp make_pair
#define X first
#define Y second
#define taskname "Boat"

using namespace std;

typedef long long ll;
typedef pair <int, int> ii;

const int N = 502;
const int MOD = 1e9 + 7;

int n, a[N], b[N];
int nX, x[2 * N], inv[N], dp[2][N * 2][N], sumDp[N * 2][N];

void readInput(){
    cin >> n;
    for(int i = 1; i <= n; i++)
        cin >> a[i] >> b[i];
}

void compress(){
    for(int i = 1; i <= n; i++){
        x[++nX] = a[i];
        x[++nX] = ++b[i];
    }
    sort(x + 1, x + 1 + nX);
    nX = unique(x + 1, x + 1 + nX) - (x + 1);
    for(int i = 1; i <= n; i++){
        a[i] = lower_bound(x + 1, x + 1 + nX, a[i]) - x;
        b[i] = lower_bound(x + 1, x + 1 + nX, b[i]) - x;
    }
}

int powMod(int x, int k){
    if (k == 0)
        return 1;
    int res = powMod(x, k >> 1);
    res = (ll) res * res % MOD;
    if (k & 1)
        res = (ll) res * x % MOD;
    return res;
}

void prepare(){
    for(int i = 1; i <= n; i++)
        b[i]--;
    inv[0] = 1;
    for(int i = 1; i <= n; i++)
        inv[i] = powMod(i, MOD - 2);
}

void add(int &x, int y){
    x += y;
    x -= (x >= MOD) * MOD;
}

void solve(){
    for(int i = 0; i < n; i++){
        int id = i & 1;
        for(int j = 1; j < nX; j++){
            int len = x[j + 1] - x[j];
            int maxK = min(n, len);
            for(int k = 1; k <= maxK; k++)
                dp[id ^ 1][j][k] = 0;
        }

        int sum = 1;
        for(int j = 1; j < nX; j++){
            int len = x[j + 1] - x[j];
            int maxK = min(n, len);
            if (a[i + 1] <= j && j <= b[i + 1])
                add(dp[id ^ 1][j][1], (ll) sum * len % MOD);
            for(int k = 1; k <= maxK; k++){
                add(sum, sumDp[j][k]);
                if (a[i + 1] <= j && j <= b[i + 1] && k < maxK)
                    add(dp[id ^ 1][j][k + 1], (ll) sumDp[j][k] * (len - k) % MOD * inv[k + 1] % MOD);
            }
        }
        for(int j = 1; j < nX; j++){
            int maxK = min(n, x[j + 1] - x[j]);
            for(int k = 1; k <= maxK; k++)
                add(sumDp[j][k], dp[id ^ 1][j][k]);
        }
    }

    int res = 0;
    for(int j = 1; j < nX; j++){
        int maxK = min(n, x[j + 1] - x[j]);
        for(int k = 1; k <= maxK; k++)
            add(res, sumDp[j][k]);
    }
    cout << res;
}

int main(){
    if (fopen(taskname".inp", "r")){
        freopen(taskname".inp", "r", stdin);
        freopen(taskname".out", "w", stdout);
    }
    readInput();
    compress();
    prepare();
    solve();
    return 0;
}

Compilation message

boat.cpp: In function 'int main()':
boat.cpp:101:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  101 |         freopen(taskname".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
boat.cpp:102:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  102 |         freopen(taskname".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 453 ms 6264 KB Output is correct
2 Correct 485 ms 6264 KB Output is correct
3 Correct 451 ms 6264 KB Output is correct
4 Correct 457 ms 6264 KB Output is correct
5 Correct 452 ms 6268 KB Output is correct
6 Correct 453 ms 6264 KB Output is correct
7 Correct 451 ms 6264 KB Output is correct
8 Correct 452 ms 6264 KB Output is correct
9 Correct 446 ms 6268 KB Output is correct
10 Correct 457 ms 6260 KB Output is correct
11 Correct 494 ms 6260 KB Output is correct
12 Correct 453 ms 6264 KB Output is correct
13 Correct 454 ms 6264 KB Output is correct
14 Correct 457 ms 6264 KB Output is correct
15 Correct 470 ms 6264 KB Output is correct
16 Correct 72 ms 1408 KB Output is correct
17 Correct 79 ms 1408 KB Output is correct
18 Correct 75 ms 1440 KB Output is correct
19 Correct 81 ms 1528 KB Output is correct
20 Correct 83 ms 1464 KB Output is correct

Subtask #2
22.0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 453 ms 6264 KB Output is correct
2 Correct 485 ms 6264 KB Output is correct
3 Correct 451 ms 6264 KB Output is correct
4 Correct 457 ms 6264 KB Output is correct
5 Correct 452 ms 6268 KB Output is correct
6 Correct 453 ms 6264 KB Output is correct
7 Correct 451 ms 6264 KB Output is correct
8 Correct 452 ms 6264 KB Output is correct
9 Correct 446 ms 6268 KB Output is correct
10 Correct 457 ms 6260 KB Output is correct
11 Correct 494 ms 6260 KB Output is correct
12 Correct 453 ms 6264 KB Output is correct
13 Correct 454 ms 6264 KB Output is correct
14 Correct 457 ms 6264 KB Output is correct
15 Correct 470 ms 6264 KB Output is correct
16 Correct 72 ms 1408 KB Output is correct
17 Correct 79 ms 1408 KB Output is correct
18 Correct 75 ms 1440 KB Output is correct
19 Correct 81 ms 1528 KB Output is correct
20 Correct 83 ms 1464 KB Output is correct
21 Correct 36 ms 5760 KB Output is correct
22 Correct 44 ms 5760 KB Output is correct
23 Correct 36 ms 5632 KB Output is correct
24 Correct 37 ms 5760 KB Output is correct
25 Correct 36 ms 5632 KB Output is correct
26 Correct 30 ms 5504 KB Output is correct
27 Correct 30 ms 5632 KB Output is correct
28 Correct 30 ms 5504 KB Output is correct
29 Correct 30 ms 5504 KB Output is correct
30 Correct 423 ms 6144 KB Output is correct
31 Correct 419 ms 6392 KB Output is correct
32 Correct 425 ms 6264 KB Output is correct
33 Correct 433 ms 6392 KB Output is correct
34 Correct 418 ms 6264 KB Output is correct
35 Correct 412 ms 6264 KB Output is correct
36 Correct 414 ms 6392 KB Output is correct
37 Correct 426 ms 6372 KB Output is correct
38 Correct 415 ms 6264 KB Output is correct

Subtask #3
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 1536 KB Output is correct
2 Correct 12 ms 1536 KB Output is correct
3 Correct 13 ms 1536 KB Output is correct
4 Correct 12 ms 1536 KB Output is correct
5 Correct 13 ms 1536 KB Output is correct
6 Correct 15 ms 1536 KB Output is correct
7 Correct 14 ms 1536 KB Output is correct
8 Correct 15 ms 1536 KB Output is correct
9 Correct 15 ms 1536 KB Output is correct
10 Correct 15 ms 1536 KB Output is correct
11 Correct 13 ms 1536 KB Output is correct
12 Correct 12 ms 1536 KB Output is correct
13 Correct 13 ms 1536 KB Output is correct
14 Correct 13 ms 1664 KB Output is correct
15 Correct 13 ms 1664 KB Output is correct
16 Correct 6 ms 1024 KB Output is correct
17 Correct 6 ms 1024 KB Output is correct
18 Correct 6 ms 1024 KB Output is correct
19 Correct 6 ms 1024 KB Output is correct
20 Correct 6 ms 1024 KB Output is correct

Subtask #4
42.0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 453 ms 6264 KB Output is correct
2 Correct 485 ms 6264 KB Output is correct
3 Correct 451 ms 6264 KB Output is correct
4 Correct 457 ms 6264 KB Output is correct
5 Correct 452 ms 6268 KB Output is correct
6 Correct 453 ms 6264 KB Output is correct
7 Correct 451 ms 6264 KB Output is correct
8 Correct 452 ms 6264 KB Output is correct
9 Correct 446 ms 6268 KB Output is correct
10 Correct 457 ms 6260 KB Output is correct
11 Correct 494 ms 6260 KB Output is correct
12 Correct 453 ms 6264 KB Output is correct
13 Correct 454 ms 6264 KB Output is correct
14 Correct 457 ms 6264 KB Output is correct
15 Correct 470 ms 6264 KB Output is correct
16 Correct 72 ms 1408 KB Output is correct
17 Correct 79 ms 1408 KB Output is correct
18 Correct 75 ms 1440 KB Output is correct
19 Correct 81 ms 1528 KB Output is correct
20 Correct 83 ms 1464 KB Output is correct
21 Correct 36 ms 5760 KB Output is correct
22 Correct 44 ms 5760 KB Output is correct
23 Correct 36 ms 5632 KB Output is correct
24 Correct 37 ms 5760 KB Output is correct
25 Correct 36 ms 5632 KB Output is correct
26 Correct 30 ms 5504 KB Output is correct
27 Correct 30 ms 5632 KB Output is correct
28 Correct 30 ms 5504 KB Output is correct
29 Correct 30 ms 5504 KB Output is correct
30 Correct 423 ms 6144 KB Output is correct
31 Correct 419 ms 6392 KB Output is correct
32 Correct 425 ms 6264 KB Output is correct
33 Correct 433 ms 6392 KB Output is correct
34 Correct 418 ms 6264 KB Output is correct
35 Correct 412 ms 6264 KB Output is correct
36 Correct 414 ms 6392 KB Output is correct
37 Correct 426 ms 6372 KB Output is correct
38 Correct 415 ms 6264 KB Output is correct
39 Correct 13 ms 1536 KB Output is correct
40 Correct 12 ms 1536 KB Output is correct
41 Correct 13 ms 1536 KB Output is correct
42 Correct 12 ms 1536 KB Output is correct
43 Correct 13 ms 1536 KB Output is correct
44 Correct 15 ms 1536 KB Output is correct
45 Correct 14 ms 1536 KB Output is correct
46 Correct 15 ms 1536 KB Output is correct
47 Correct 15 ms 1536 KB Output is correct
48 Correct 15 ms 1536 KB Output is correct
49 Correct 13 ms 1536 KB Output is correct
50 Correct 12 ms 1536 KB Output is correct
51 Correct 13 ms 1536 KB Output is correct
52 Correct 13 ms 1664 KB Output is correct
53 Correct 13 ms 1664 KB Output is correct
54 Correct 6 ms 1024 KB Output is correct
55 Correct 6 ms 1024 KB Output is correct
56 Correct 6 ms 1024 KB Output is correct
57 Correct 6 ms 1024 KB Output is correct
58 Correct 6 ms 1024 KB Output is correct
59 Correct 1321 ms 6284 KB Output is correct
60 Correct 1275 ms 6288 KB Output is correct
61 Correct 1279 ms 6392 KB Output is correct
62 Correct 1313 ms 6288 KB Output is correct
63 Correct 1306 ms 6272 KB Output is correct
64 Correct 1553 ms 6392 KB Output is correct
65 Correct 1539 ms 6392 KB Output is correct
66 Correct 1553 ms 6272 KB Output is correct
67 Correct 1538 ms 6392 KB Output is correct
68 Correct 1553 ms 6272 KB Output is correct
69 Correct 1274 ms 6392 KB Output is correct
70 Correct 1281 ms 6392 KB Output is correct
71 Correct 1287 ms 6392 KB Output is correct
72 Correct 1303 ms 6392 KB Output is correct
73 Correct 1299 ms 6392 KB Output is correct
74 Correct 136 ms 1408 KB Output is correct
75 Correct 135 ms 1408 KB Output is correct
76 Correct 138 ms 1408 KB Output is correct
77 Correct 133 ms 1408 KB Output is correct
78 Correct 136 ms 1456 KB Output is correct