oj.uz

Submission #218037

# Submission time Handle Problem Language Result Execution time Memory
218037 2020-03-31T14:23:40 Z perveevm Boat (APIO16_boat) C++14
9 / 100
 551 ms 2432 KB 
// #pragma comment(linker, "/stack:200000000")
// #pragma GCC optimize("Ofast,no-stack-protector")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
// #pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>

#ifdef PERVEEVM_LOCAL
    #define debug(x) std::cerr << (#x) << ":\t" << (x) << std::endl
#else
    #define debug(x) 238;
#endif

#define fastIO std::ios_base::sync_with_stdio(false); std::cin.tie(0); std::cout.tie(0)
#define NAME "File"

using ll = long long;
using ld = long double;

#ifdef PERVEEVM_LOCAL
    std::mt19937 rnd(238);
#else
    std::mt19937 rnd(std::chrono::high_resolution_clock::now().time_since_epoch().count());
#endif

const double PI = atan2(0.0, -1.0);
const int INF = 0x3f3f3f3f;
const ll LINF = (ll)2e18;
const int N = 510;
const int MOD = (int)1e9 + 7;

int add(int a, int b, int mod = MOD) {
    if (a + b >= mod) {
        return a + b - mod;
    }
    return a + b;
}

int sub(int a, int b, int mod = MOD) {
    if (a - b < 0) {
        return a - b + mod;
    }
    return a - b;
}

int mul(int a, int b, int mod = MOD) {
    return (int)(1ll * a * b % mod);
}

int binpow(int a, int n, int mod = MOD) {
    if (n == 0) {
        return 1;
    }
    if (n % 2 == 0) {
        return binpow(mul(a, a, mod), n / 2, mod);
    } else {
        return mul(binpow(a, n - 1, mod), a, mod);
    }
}

int rev(int a, int mod = MOD) {
    return binpow(a, mod - 2, mod);
}

int a[N], b[N];
int dp[2 * N][N];
int f[2 * N], rf[2 * N];

void precalc() {
    f[0] = 1;
    rf[0] = 1;

    for (int i = 1; i < 2 * N; ++i) {
        f[i] = mul(f[i - 1], i);
        rf[i] = rev(f[i]);
    }
}

int C(int n, int k) {
    if (n < k) {
        return 0;
    }
    return mul(f[n], mul(rf[k], rf[n - k]));
}

void run() {
    precalc();

    int n;
    scanf("%d", &n);

    for (int i = 1; i <= n; ++i) {
        scanf("%d%d", &a[i], &b[i]);
        ++b[i];
    }

    std::vector<int> trans;
    for (int i = 1; i <= n; ++i) {
        trans.push_back(a[i]);
        trans.push_back(b[i]);
    }

    std::sort(trans.begin(), trans.end());
    trans.resize(std::unique(trans.begin(), trans.end()) - trans.begin());

    for (int i = 1; i <= n; ++i) {
        a[i] = std::lower_bound(trans.begin(), trans.end(), a[i]) - trans.begin() + 1;
        b[i] = std::lower_bound(trans.begin(), trans.end(), b[i]) - trans.begin() + 1;
    }

    dp[0][0] = 1;
    // dp[i][j] - ans if last segment is i'th or less and last boat is j'th

    for (int i = 1; i < (int)trans.size(); ++i) {
        dp[i][0] = 1;

        for (int j = 1; j <= n; ++j) {
            dp[i][j] = dp[i - 1][j];

            if (i < a[j] || b[j] <= i) {
                continue;
            }

            int len = trans[i] - trans[i - 1];
            int cnt = 1;

            for (int k = j - 1; k >= 0; --k) {
                dp[i][j] = add(dp[i][j], mul(dp[i - 1][k], C(len + cnt - 1, cnt)));

                if (a[k] <= i && i < b[k]) {
                    ++cnt;
                }
            }
        }
    }

    int ans = 0;
    for (int i = 1; i <= n; ++i) {
        ans = add(ans, dp[(int)trans.size() - 1][i]);
    }

    printf("%d\n", ans);
}

int main(void) {
    // freopen(NAME".in", "r", stdin);
    // freopen(NAME".out", "w", stdout);

    auto start = std::chrono::high_resolution_clock::now();
    run();
    auto end = std::chrono::high_resolution_clock::now();

    #ifdef PERVEEVM_LOCAL
        std::cerr << "Execution time: "
                  << std::chrono::duration_cast<std::chrono::milliseconds>(end - start).count()
                  << " ms" << std::endl;
    #endif

    return 0;
}

Compilation message

boat.cpp: In function 'int main()':
boat.cpp:149:10: warning: variable 'start' set but not used [-Wunused-but-set-variable]
     auto start = std::chrono::high_resolution_clock::now();
          ^~~~~
boat.cpp:151:10: warning: variable 'end' set but not used [-Wunused-but-set-variable]
     auto end = std::chrono::high_resolution_clock::now();
          ^~~
boat.cpp: In function 'void run()':
boat.cpp:90:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
boat.cpp:93:14: 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 9 ms 2304 KB Output is correct
2 Correct 9 ms 2432 KB Output is correct
3 Correct 9 ms 2432 KB Output is correct
4 Correct 9 ms 2176 KB Output is correct
5 Correct 9 ms 2432 KB Output is correct
6 Correct 8 ms 2304 KB Output is correct
7 Correct 8 ms 2304 KB Output is correct
8 Correct 8 ms 2432 KB Output is correct
9 Correct 9 ms 2304 KB Output is correct
10 Correct 9 ms 2304 KB Output is correct
11 Correct 8 ms 2432 KB Output is correct
12 Correct 8 ms 2304 KB Output is correct
13 Correct 8 ms 2432 KB Output is correct
14 Correct 8 ms 2304 KB Output is correct
15 Correct 8 ms 2304 KB Output is correct
16 Correct 7 ms 640 KB Output is correct
17 Correct 7 ms 768 KB Output is correct
18 Correct 7 ms 768 KB Output is correct
19 Correct 7 ms 768 KB Output is correct
20 Correct 7 ms 768 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 2304 KB Output is correct
2 Correct 9 ms 2432 KB Output is correct
3 Correct 9 ms 2432 KB Output is correct
4 Correct 9 ms 2176 KB Output is correct
5 Correct 9 ms 2432 KB Output is correct
6 Correct 8 ms 2304 KB Output is correct
7 Correct 8 ms 2304 KB Output is correct
8 Correct 8 ms 2432 KB Output is correct
9 Correct 9 ms 2304 KB Output is correct
10 Correct 9 ms 2304 KB Output is correct
11 Correct 8 ms 2432 KB Output is correct
12 Correct 8 ms 2304 KB Output is correct
13 Correct 8 ms 2432 KB Output is correct
14 Correct 8 ms 2304 KB Output is correct
15 Correct 8 ms 2304 KB Output is correct
16 Correct 7 ms 640 KB Output is correct
17 Correct 7 ms 768 KB Output is correct
18 Correct 7 ms 768 KB Output is correct
19 Correct 7 ms 768 KB Output is correct
20 Correct 7 ms 768 KB Output is correct
21 Correct 391 ms 2124 KB Output is correct
22 Correct 379 ms 2216 KB Output is correct
23 Correct 348 ms 2168 KB Output is correct
24 Correct 380 ms 2296 KB Output is correct
25 Correct 365 ms 2144 KB Output is correct
26 Correct 541 ms 2168 KB Output is correct
27 Correct 551 ms 2296 KB Output is correct
28 Correct 534 ms 2040 KB Output is correct
29 Correct 534 ms 2296 KB Output is correct
30 Incorrect 10 ms 2304 KB Output isn't correct
31 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# Verdict Execution time Memory Grader output
1 Runtime error 5 ms 512 KB Execution killed with signal 11 (could be triggered by violating memory limits)
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 2304 KB Output is correct
2 Correct 9 ms 2432 KB Output is correct
3 Correct 9 ms 2432 KB Output is correct
4 Correct 9 ms 2176 KB Output is correct
5 Correct 9 ms 2432 KB Output is correct
6 Correct 8 ms 2304 KB Output is correct
7 Correct 8 ms 2304 KB Output is correct
8 Correct 8 ms 2432 KB Output is correct
9 Correct 9 ms 2304 KB Output is correct
10 Correct 9 ms 2304 KB Output is correct
11 Correct 8 ms 2432 KB Output is correct
12 Correct 8 ms 2304 KB Output is correct
13 Correct 8 ms 2432 KB Output is correct
14 Correct 8 ms 2304 KB Output is correct
15 Correct 8 ms 2304 KB Output is correct
16 Correct 7 ms 640 KB Output is correct
17 Correct 7 ms 768 KB Output is correct
18 Correct 7 ms 768 KB Output is correct
19 Correct 7 ms 768 KB Output is correct
20 Correct 7 ms 768 KB Output is correct
21 Correct 391 ms 2124 KB Output is correct
22 Correct 379 ms 2216 KB Output is correct
23 Correct 348 ms 2168 KB Output is correct
24 Correct 380 ms 2296 KB Output is correct
25 Correct 365 ms 2144 KB Output is correct
26 Correct 541 ms 2168 KB Output is correct
27 Correct 551 ms 2296 KB Output is correct
28 Correct 534 ms 2040 KB Output is correct
29 Correct 534 ms 2296 KB Output is correct
30 Incorrect 10 ms 2304 KB Output isn't correct
31 Halted 0 ms 0 KB -