Submission #637724

#TimeUsernameProblemLanguageResultExecution timeMemory
637724lovrotBoat (APIO16_boat)C++11
27 / 100
2079 ms14852 KiB
#include <bits/stdc++.h> #define ll long long #define pii pair<ll, ll> #define X first #define Y second #define pb push_back using namespace std; const int N = 1010; const ll MOD = 1e9 + 7; ll n, intcnt, l[N], r[N]; ll siz[N], fact[N], povrh[N][N], calc[N][N]; ll dp[N][N]; int u[N][N]; vector<pii> intv; vector<ll> v; ll add(ll a, ll b){ return (a + b >= MOD ? a + b - MOD : a + b); } ll mult(ll a, ll b){ return a * b % MOD; } ll fastpow(ll b, ll e){ ll ret = 1; while(e){ if(e & 1) ret = mult(ret, b); b = mult(b, b); e >>= 1; } return ret; } ll divd(ll a, ll b){ return mult(a, fastpow(b, MOD - 2)); } void precompute(){ fact[0] = 1; for(int i = 1; i < N; i++) fact[i] = mult(fact[i - 1], i); for(int i = 0; i < N / 2; i++) for(int j = 0; j <= i; j++) povrh[i][j] = divd(fact[i], mult(fact[j], fact[i - j])); for(int i = 0; i < intcnt; i++){ ll sfact = 1; for(ll k = 1; k <= n; k++){ ll sfact = 1; for(ll j = 1; j <= min(k, siz[i]); j++){ sfact = mult(sfact, siz[i] - j + 1); calc[i][k] = add(calc[i][k], mult(povrh[k - 1][j - 1], divd(sfact, fact[j]))); } } } } ll DP(int x, int b){ if(b >= intcnt) return 1; if(dp[x][b] != -1) return dp[x][b]; dp[x][b] = DP(x, b + 1); int cnt = 0; for(int i = x; i < n; i++){ cnt += u[i][b]; if(u[i][b]) dp[x][b] = add(dp[x][b], mult(calc[b][cnt], DP(i + 1, b + 1))); } // printf("%d %lld %lld s: %lld\n", x, b, dp[x][b], calc[b][2]); return dp[x][b]; } int main(){ for(int i = 0; i < N; i++) for(int j = 0; j < N; j++) dp[i][j] = -1; scanf("%d", &n); for(int i = 0; i < n; i++){ scanf("%lld%lld", &l[i], &r[i]); v.pb(l[i]); v.pb(r[i]); } sort(v.begin(), v.end()); v.resize(unique(v.begin(), v.end()) - v.begin()); for(int i = 0; i < v.size(); i++){ if(i != 0 && v[i - 1] < v[i] - 1){ intv.pb({v[i - 1] + 1, v[i] - 1}); } intv.pb({v[i], v[i]}); } intcnt = intv.size(); for(int i = 0; i < intcnt; i++) siz[i] = intv[i].Y - intv[i].X + 1; for(int i = 0; i < n; i++){ for(ll j = 0; j < intcnt; j++){ if(intv[j].X >= l[i] && intv[j].Y <= r[i]){ u[i][j] = true; } } // printf("%d %d %d\n", i, poc[i], kraj[i]); } precompute(); printf("%lld\n", add(DP(0, 0), MOD - 1)); return 0; }

Compilation message (stderr)

boat.cpp: In function 'void precompute()':
boat.cpp:51:6: warning: unused variable 'sfact' [-Wunused-variable]
   51 |   ll sfact = 1;
      |      ^~~~~
boat.cpp: In function 'int main()':
boat.cpp:81:10: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'long long int*' [-Wformat=]
   81 |  scanf("%d", &n);
      |         ~^   ~~
      |          |   |
      |          |   long long int*
      |          int*
      |         %lld
boat.cpp:92:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   92 |  for(int i = 0; i < v.size(); i++){
      |                 ~~^~~~~~~~~~
boat.cpp:81:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   81 |  scanf("%d", &n);
      |  ~~~~~^~~~~~~~~~
boat.cpp:84:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   84 |   scanf("%lld%lld", &l[i], &r[i]);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
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