Submission #884338

#	Time	Username	Problem	Language	Result	Execution time	Memory
884338		Kevin_Zhang_TW	Giraffes (JOI22_giraffes)	C++17	59 / 100	54 ms	56356 KiB

giraffes

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb emplace_back
#define AI(i) begin(i), end(i)
template<class T> bool chmin(T &a, T b) { return b < a && (a = b, true); }
template<class T> bool chmax(T &a, T b) { return a < b && (a = b, true); }
#ifdef KEV
#define DE(args...) kout("[ " + string(#args) + " ] = ", args)
void kout() { cerr << endl; }
template<class T, class ...U> void kout(T a, U ...b) { cerr << a << ' ', kout(b...); }
template<class T> void debug(T l, T r) { while (l != r) cerr << *l << " \n"[next(l)==r], ++l; }
#else
#define DE(...) 0
#define debug(...) 0
#endif
// My bug list :
// integer overflow
// 0based, 1based forgotten
// index out of bound
// n, m, i, j typo
// some cases are missing

const int MAX_N = 310;

int n, p[MAX_N];
int dp[MAX_N][MAX_N][MAX_N];

int32_t main() {
  ios_base::sync_with_stdio(0), cin.tie(0);
  cin >> n;
  if (n > 300) return 0;
  for (int i = 1;i <= n;++i)
    cin >> p[i];

  int res = 0;

  for (int l = 0;l <= n;++l)
    for (int r = n+1;r > l+1;--r) {
      int sz = l + n - r + 1;
      //DE(l, r, sz);
      for (int i = 0, lidx = 0, ridx = n - sz + 1;i <= sz;++i, ++lidx, ++ridx) {
        //DE(lidx, ridx);
        chmax(dp[l+1][r][i+1], dp[l][r][i] + (p[lidx+1] == l+1));
        chmax(dp[l+1][r][i], dp[l][r][i] + (p[ridx-1] == l+1));

        chmax(dp[l][r-1][i+1], dp[l][r][i] + (p[lidx+1] == r-1));
        chmax(dp[l][r-1][i], dp[l][r][i] + (p[ridx-1] == r-1));
      }
    }
      //DE(l, r, sz);
//      for (int i = 0;i <= sz;++i) {
//        int j = sz - i;
//        int mn = i + 1, mx = n - j;
//        chmax(dp[l+1][r][i+1], dp[l][r][i] + (p[l+1] == mn));
//        chmax(dp[l+1][r][i], dp[l][r][i] + (p[l+1] == mx));
//        chmax(dp[l][r-1][i+1], dp[l][r][i] + (p[r-1] == mn));
//        chmax(dp[l][r-1][i], dp[l][r][i] + (p[r-1] == mx));
//      }

  for (int i = 0;i <= n;++i)
    for (int j = 0;j <= n;++j)
      chmax(res, dp[i][i+1][j]);
  cout << n - res << '\n';


}

	
	

• Subtask 1: 10 / 10
• Subtask 2: 22 / 22
• Subtask 3: 27 / 27
• Subtask 4: 0 / 41