Submission #242932

#	Time	Username	Problem	Language	Result	Execution time	Memory
242932		Bruteforceman	Vim (BOI13_vim)	C++11	42.50 / 100	40 ms	2296 KiB

vim

#include <bits/stdc++.h>
using namespace std;
const int inf = 1e8;
const int maxn = 5005; // 7e4 + 10;
const int alpha = 10;
string s;
int n;
int nxt[alpha][maxn];
int opt[maxn];
map <pair <int, int>, int> mem;
int cnt[maxn];

int dp(int now, int done) {
  int jump = opt[done];
  if(jump == n) return 0;
  if(mem.find(make_pair(now, done)) != mem.end()) {
    return mem[make_pair(now, done)];
  }
  int ans = inf;
  for(int i = 0; i < alpha; i++) {
    if(i != 'e' - 'a' && nxt[i][now] < n) {
      int idx = nxt[i][now];
      if(idx < jump) {
        ans = min(ans, 2 + dp(idx, max(done, idx)));
      } else {
        ans = min(ans, 2 + dp(jump, idx) + cnt[idx] - cnt[jump]);
      }
    }
  }
  return mem[make_pair(now, done)] = ans;
}
int main() {
  cin >> n >> s;
  vector <int> aux (alpha, n);
  for(int i = n - 1; i >= 0; i--) {
    for(int j = 0; j < alpha; j++) {
      nxt[j][i] = aux[j];
    }
    aux[s[i] - 'a'] = i;
  }
  int var = n;
  for(int i = n - 1; i >= 0; i--) {
    opt[i] = var;
    if(i > 0 && s[i - 1] == 'e' && s[i] != 'e') {
      var = i;
    }
  }
  int total = 0;
  for(int i = 0; i < n; i++) {
    total += (s[i] != 'e');
    cnt[i] = total;
  }
  int ans = 2 * count(s.begin(), s.end(), 'e');
  cout << ans + dp(0, 0) << endl;
}

• Subtask 1: 37.5 / 50
• Subtask 2: 5 / 10
• Subtask 3: 0 / 40