Submission #93092

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Source Code Expand

#include <iostream>
#include <cassert>
#include <string>
#include <cctype>
using namespace std;

typedef long long ll;
#define REP(i, n) for(int i = 0; i < (int)(n); i++)

ll size(const string &str, size_t &cur);

ll Number(const string &str, size_t &cur){
  ll res = 0;
  while(cur < str.size() && isdigit(str[cur])){
    res = res * 10 + str[cur++] - '0';
  }
  return res;
}

string String(const string &str, size_t &cur){
  ll l = cur;
  assert(isalpha(str[cur]));
  while(cur < str.size() && isalpha(str[cur])) cur++;
  return string(str.begin() + l, str.begin() + cur);
}

ll size_str(const string &str, size_t &cur){
  if(str[cur] == '('){
    ll len = size(str, ++cur);
    assert(str[cur++] == ')');
    return len * Number(str, cur);
  }else{
    return String(str, cur).size();
  }
}

ll size(const string &str, size_t &cur){
  ll s = size_str(str, cur);
  while(cur < str.size() && str[cur] != ')'){
    s += size_str(str, cur);
  }
  return s;
}

ll size(const string &str){
  size_t cur = 0;
  return size(str, cur);
}

string expr(const string &str, size_t &cur, ll s, ll e);

string exp_str(const string &str, size_t &cur, ll s, ll e){
  if(s >= e) return string("");
  
  if(str[cur] == '('){
    string ans(e - s, ' ');
    string ret;
    string full;
    
    size_t tot = 0;
    
    size_t old_cur = ++cur;
    ll len = size(str, cur);
    assert(str[cur++] == ')');
    ll tot_len = len * Number(str, cur);
    ll start = s / len * len;

    while(start < e && start < tot_len){
      size_t tmp_cur = old_cur;
      ll tmp_s = max(0LL, s - start);
      ll tmp_e = min(max(0LL, e - start), len);
      
      if(tmp_e - tmp_s == len){
	if(full == ""){
	  full = ret = expr(str, tmp_cur, tmp_s, tmp_e);
	}else{
	  ret = full;
	}
      }else{
	ret = expr(str, tmp_cur, tmp_s, tmp_e);
      }
      REP(i, ret.size()) ans[tot + i] = ret[i];
      tot += ret.size();
      start += len;
    }
    assert(ans.size() == tot);
    return ans;
  }else{
    string t = String(str, cur);
    return string(t.begin() + s, t.begin() + e);
  }
};

string expr(const string &str, size_t &cur, ll s, ll e){
  if(s >= e) string("");;
  string ans(e - s, ' ');
  string ret;
  size_t tot = 0;
  size_t len_cur = cur;
  ll len = size_str(str, len_cur);
  
  if(s < min(len, e)){
    ret = exp_str(str, cur, s, min(len, e));
    REP(i, ret.size()) ans[i] = ret[i];
    tot += ret.size();
  }
  
  cur = len_cur;
  s = max(0LL, s - len);
  e = max(0LL, e - len);
  
  while(cur < str.size() && str[cur] != ')'){
    ll len = size_str(str, len_cur);
    if(s < min(len, e)){
      ret = exp_str(str, cur, s, min(len, e));
      REP(i, ret.size()) ans[tot + i] = ret[i];
      tot += ret.size();
    }
    cur = len_cur;
    s = max(0LL, s - len);
    e = max(0LL, e - len);
  }
  
  // cout << tot << " " << ans.size()
  //      << " " << s << " " << e << endl
  // cout << ans << endl;
  
  assert(tot == ans.size());
  return ans;
}
		
string solve(const string &str, ll s, ll e){
  size_t cur = 0;
  return expr(str, cur, s, e);
}


int main(){
  ll B, L, N, M;
  string S;
  cin >> B >> L >> N >> S;
  M = size(S);
  if(B < 0) B = M+ B;
  cout << solve(S, B, B + L) << endl;
  return 0;
}

Submission Info

Judge Result