oj.uz

Submission #825752

# Submission time Handle Problem Language Result Execution time Memory
825752 2023-08-15T07:40:35 Z GrindMachine Boat (APIO16_boat) C++17
0 / 100
 855 ms 12364 KB 
// Om Namah Shivaya

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a, b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a, b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*



*/

const int MOD = 1e9 + 7;
const int N = 500 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

ll fact[N], ifact[N];

ll bexp(ll a, ll b) {
    a %= MOD;
    if (a == 0) return 0;

    ll res = 1;

    while (b) {
        if (b & 1) res = res * a % MOD;
        a = a * a % MOD;
        b >>= 1;
    }

    return res;
}

ll invmod(ll a) {
    return bexp(a, MOD - 2);
}

ll ncr(ll n, ll r) {
    if (n < 0 or r < 0 or n < r) return 0;
    return fact[n] * ifact[r] % MOD * ifact[n - r] % MOD;
}

ll npr(ll n, ll r) {
    if (n < 0 or r < 0 or n < r) return 0;
    return fact[n] * ifact[n - r] % MOD;
}

void precalc(ll n) {
    fact[0] = 1;
    rep1(i, n) fact[i] = fact[i - 1] * i % MOD;

    ifact[n] = invmod(fact[n]);
    rev(i, n - 1, 0) ifact[i] = ifact[i + 1] * (i + 1) % MOD;
}

void solve(int test_case)
{
    precalc(N-1);

    ll n; cin >> n;
    vector<pll> a(n+5);
    rep1(i,n) cin >> a[i].ff >> a[i].ss;

    vector<ll> b;
    rep1(i,n) b.pb(a[i].ff), b.pb(a[i].ss);
    sort(all(b));
    b.resize(unique(all(b))-b.begin());

    vector<pll> ranges;
    ranges.pb({0,0});
    rep(i,sz(b)){
        ranges.pb({b[i],b[i]});
        if(i+1 < sz(b)){
            if(b[i]+1 <= b[i+1]-1){
                ranges.pb({b[i]+1,b[i+1]-1});
            }   
        }
    }

    ll m = sz(ranges);

    ll choose[m+5][n+5];
    memset(choose,0,sizeof choose);

    rep(i,m){
        auto [l,r] = ranges[i];
        ll len = r-l+1;
        choose[i][0] = 1;
        ll curr = 1;

        rep1(r,n){
            if(len < r) break;
            curr = curr * (len-r+1) % MOD;
            choose[i][r] = curr * ifact[r] % MOD;
        }
    }

    auto isect = [&](pll p1, pll p2){
        return max(p1.ff,p2.ff) <= min(p1.ss,p2.ss);
    };

    ll choose_ways[m+5][n+5];
    memset(choose_ways,0,sizeof choose_ways);

    rep(i,m){
        choose_ways[i][0] = 1;
        choose_ways[i][1] = choose[i][1];

        for(int j = 2; j <= n; ++j){
            // endpoints fixed i.e 2 of these j guys are always chosen
            // decide pick/ignore for rest j-2 guys
            rep(more,j-2+1){
                ll ways = ncr(j-2,more)*choose[j][more+2]%MOD;
                choose_ways[i][j] += ways;
                choose_ways[i][j] %= MOD;
            }
        }
    }

    // debug(ranges);
    // debug(choose[2][1]);

    ll dp[n+5][m+5];
    memset(dp,0,sizeof dp);
    rep(j,m+5) dp[0][j] = 1;

    rep1(i,n){
        dp[i][0] = 1;
        rep1(j,m-1){
            dp[i][j] = (dp[i-1][j]+dp[i][j-1]-dp[i-1][j-1]+MOD)%MOD;
            if(!isect(a[i],ranges[j])) conts;

            dp[i][j] += choose[j][1]*dp[i-1][j-1];
            dp[i][j] %= MOD;

            ll good = 1;

            rev(k,i-1,1){
                // i and k fixed
                // few more in between
                if(isect(a[k],ranges[j])){
                    good++;
                    dp[i][j] += choose_ways[j][good]*dp[k-1][j-1];
                    dp[i][j] %= MOD;
                    // rep(more,good-2+1){
                    //     ll choose_guys = ncr(good-2,more);
                    //     ll choose_points = choose[j][more+2];
                    //     ll choose_ways = choose_guys*choose_points % MOD;
                    //     dp[i][j] += choose_ways*dp[k-1][j-1];
                    //     dp[i][j] %= MOD;
                    // }
                }
            }
        }
    }

    ll ans = (dp[n][m-1]-1+MOD)%MOD;
    cout << ans << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

Compilation message

boat.cpp: In function 'void solve(int)':
boat.cpp:30:36: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 | #define rep(i, n) for(int i = 0; i < n; ++i)
      |                                    ^
boat.cpp:116:5: note: in expansion of macro 'rep'
  116 |     rep(i,sz(b)){
      |     ^~~
boat.cpp:118:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  118 |         if(i+1 < sz(b)){
      |                ^

Subtask #1
0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 811 ms 12260 KB Output is correct
2 Correct 844 ms 12264 KB Output is correct
3 Correct 808 ms 12268 KB Output is correct
4 Correct 812 ms 12268 KB Output is correct
5 Correct 851 ms 12264 KB Output is correct
6 Correct 820 ms 12268 KB Output is correct
7 Correct 804 ms 12268 KB Output is correct
8 Correct 809 ms 12264 KB Output is correct
9 Correct 809 ms 12264 KB Output is correct
10 Correct 839 ms 12264 KB Output is correct
11 Correct 855 ms 12264 KB Output is correct
12 Correct 814 ms 12268 KB Output is correct
13 Correct 798 ms 12268 KB Output is correct
14 Correct 815 ms 12152 KB Output is correct
15 Correct 823 ms 12364 KB Output is correct
16 Runtime error 3 ms 3412 KB Execution killed with signal 11
17 Halted 0 ms 0 KB -

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 811 ms 12260 KB Output is correct
2 Correct 844 ms 12264 KB Output is correct
3 Correct 808 ms 12268 KB Output is correct
4 Correct 812 ms 12268 KB Output is correct
5 Correct 851 ms 12264 KB Output is correct
6 Correct 820 ms 12268 KB Output is correct
7 Correct 804 ms 12268 KB Output is correct
8 Correct 809 ms 12264 KB Output is correct
9 Correct 809 ms 12264 KB Output is correct
10 Correct 839 ms 12264 KB Output is correct
11 Correct 855 ms 12264 KB Output is correct
12 Correct 814 ms 12268 KB Output is correct
13 Correct 798 ms 12268 KB Output is correct
14 Correct 815 ms 12152 KB Output is correct
15 Correct 823 ms 12364 KB Output is correct
16 Runtime error 3 ms 3412 KB Execution killed with signal 11
17 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 15 ms 1260 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 811 ms 12260 KB Output is correct
2 Correct 844 ms 12264 KB Output is correct
3 Correct 808 ms 12268 KB Output is correct
4 Correct 812 ms 12268 KB Output is correct
5 Correct 851 ms 12264 KB Output is correct
6 Correct 820 ms 12268 KB Output is correct
7 Correct 804 ms 12268 KB Output is correct
8 Correct 809 ms 12264 KB Output is correct
9 Correct 809 ms 12264 KB Output is correct
10 Correct 839 ms 12264 KB Output is correct
11 Correct 855 ms 12264 KB Output is correct
12 Correct 814 ms 12268 KB Output is correct
13 Correct 798 ms 12268 KB Output is correct
14 Correct 815 ms 12152 KB Output is correct
15 Correct 823 ms 12364 KB Output is correct
16 Runtime error 3 ms 3412 KB Execution killed with signal 11
17 Halted 0 ms 0 KB -