Submission #259201

#	Time	Username	Problem	Language	Result	Execution time	Memory
259201		Haunted_Cpp	Calvinball championship (CEOI15_teams)	C++17	100 / 100	388 ms	632 KiB

teams

/**
 *  author: Haunted_Cpp
**/
 
#include <bits/stdc++.h>
using namespace std;
 
#pragma GCC optimize("Ofast")
#pragma GCC target("fma,sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#pragma GCC optimize("unroll-loops")
 
template<typename T> ostream &operator << (ostream &os, const vector<T> &v) { os << '{'; string sep; for (const auto &x : v) os << sep << x, sep = ", "; return os << '}'; }
template<typename T, size_t size> ostream &operator << (ostream &os, const array<T, size> &arr) { os << '{'; string sep; for (const auto &x : arr) os << sep << x, sep = ", "; return os << '}'; }
template<typename A, typename B> ostream &operator << (ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ", " << p.second << ')'; }
 
void debug_out() { cerr << endl; }
template<typename Head, typename... Tail> void debug_out(Head H, Tail... T) { cerr << ' ' << H; debug_out(T...); }
 
#ifdef LOCAL
#define debug(...) cerr << "(" << #__VA_ARGS__ << "):", debug_out(__VA_ARGS__)
#else
#define debug(...) 47
#endif

const int N = 1e4 + 5;
const int MOD = 1e6 + 7;

int dp[2][N][2];
int arr[N];

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

int mult(int a, int b) {
  long long res = 1LL * a * b;
  if (res >= MOD) res %= MOD;
  return res;
}

int main () {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> arr[i];
  dp[0][1][0] = 1;
  for (int i = 1; i < n; i++) {
    for (int j = 1; j <= i + 1; j++) {
      // Reach a new maximum
      if(j < arr[i]) {
        dp[i&1][j][1] = add(dp[i&1][j][1], dp[(i-1)&1][j-1][0]);
        dp[i&1][j][1] = add(dp[i&1][j][1], dp[(i-1)&1][j-1][1]);
      } else if (j == arr[i]) {
        dp[i&1][j][0] = add(dp[i&1][j][0], dp[(i-1)&1][j-1][0]);
        dp[i&1][j][1] = add(dp[i&1][j][1], dp[(i-1)&1][j-1][1]);
      } else {
        dp[i&1][j][1] = add(dp[i&1][j][1], dp[(i-1)&1][j-1][1]);
      }
      // Just use some old value, keep maximum
      dp[i&1][j][1] = add(dp[i&1][j][1], mult(dp[(i-1)&1][j][1], j));
      dp[i&1][j][1] = add(dp[i&1][j][1], mult(dp[(i-1)&1][j][0], min(j, arr[i] - 1)));
      if (j >= arr[i]) dp[i&1][j][0] = add(dp[i&1][j][0], dp[(i-1)&1][j][0]);
    }
    memset(dp[(i+1)&1], 0, sizeof(dp[(i+1)&1]));
  }
  int res = 0;
  for (int i = 1; i <= n; i++) {
    res = add(res, dp[(n - 1) & 1][i][0]);
    res = add(res, dp[(n - 1) & 1][i][1]);
  }
  cout << res << '\n';
  return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10