Submission #824408

#	Time	Username	Problem	Language	Result	Execution time	Memory
824408		kwongweng	Homework (CEOI22_homework)	C++17	100 / 100	84 ms	83580 KiB

Main

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef long double ld;
typedef pair<ll, ll> pll;
#define FOR(i, a, b) for(int i = a; i < b; i++)
#define ROF(i, a, b) for(int i = a; i >= b; i--)
#define ms memset
#define pb push_back
#define fi first
#define se second

string s;
int nxt[7000000]; 
/*corresponding , to each (), to split the expression into two
Main obs : all reachable values fall within a continuous interval
range returns 2 values {A,B}
A -> A smallest values cannot be reached
B -> B largest values cannot be reached
*/
ii range(int L, int R){
  if (L==R) return {0,0}; // ?
  ii val1 = range(L+4,nxt[L+3]-1);
  ii val2 = range(nxt[L+3]+1,R-1);
  if (s[L+2]=='x'){
    //max
    return {val1.fi+val2.fi+1, min(val1.se, val2.se)};
  }
  //min
  return {min(val1.fi, val2.fi), val1.se+val2.se+1};
}

void solve(){
  cin>>s; int len=s.size();
  ms(nxt,-1,sizeof(nxt));
  stack<int> st; int cnt=0;
  FOR(i,0,len){
    if (s[i]=='(') st.push(i);
    if (s[i]==','){nxt[st.top()]=i; st.pop();}
    if (s[i]=='?') cnt++;
  }
  ii ans = range(0,len-1);
  cout<<cnt-ans.fi-ans.se<<'\n';
}

int main(){
	//MOD=MOD1;
    ios::sync_with_stdio(false);
    if (fopen("input.txt", "r")) {
		  freopen("input.txt", "r", stdin);
    	freopen("output.txt", "w", stdout);
	  }
    int TC = 1;
    //cin >> TC; 
    FOR(i, 1, TC+1){
        //cout << "Case #" << i << ": ";
        solve();
    }
	
	return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:53:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   53 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:54:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   54 |      freopen("output.txt", "w", stdout);
      |      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 13 / 13
• Subtask 4: 30 / 30
• Subtask 5: 34 / 34