Submission #504078

#	Time	Username	Problem	Language	Result	Execution time	Memory
504078		Carmel_Ab1	Linear Garden (IOI08_linear_garden)	C++17	20 / 100	1578 ms	6072 KiB

linear_garden

/*
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
 */
#include<bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>

//using namespace __gnu_pbds;
using namespace std;

typedef long double ld;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int>vi;
typedef vector<vector<int>>vvi;
typedef vector<ll>vl;
typedef vector<vl> vvl;
typedef pair<int,int>pi;
typedef pair<ll,ll> pl;
typedef vector<pl> vpl;
typedef vector<ld> vld;
typedef pair<ld,ld> pld;
typedef vector<pi> vpi;

//typedef tree<ll, null_type, less_equal<ll>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
template<typename T> ostream& operator<<(ostream& os, vector<T>& a){os<<"[";for(int i=0; i<ll(a.size()); i++){os << a[i] << ((i!=ll(a.size()-1)?" ":""));}os << "]\n"; return os;}

#define all(x) x.begin(),x.end()
#define YES out("YES")
#define NO out("NO")
#define out(x){cout << x << "\n"; return;}
#define outfl(x){cout << x << endl;return;}
#define GLHF ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
#define print(x){for(auto ait:x) cout << ait << " "; cout << "\n";}
#define pb push_back
#define umap unordered_map

template<typename T1, typename T2> istream& operator>>(istream& is, pair<T1, T2>& p){is >> p.first >> p.second;return is;}
template<typename T1, typename T2> ostream& operator<<(ostream& os, pair<T1, T2>& p){os <<"" << p.first << " " << p.second << ""; return os;}
void usaco(string taskname){
    string fin = taskname + ".in";
    string fout = taskname + ".out";
    const char* FIN = fin.c_str();
    const char* FOUT = fout.c_str();
    freopen(FIN, "r", stdin);
    freopen(FOUT, "w", stdout);
}
template<typename T>
void read(vector<T>& v){
    int n=v.size();
    for(int i=0; i<n; i++)
        cin >> v[i];
}
template<typename T>
vector<T>UNQ(vector<T>a){
    vector<T>ans;
    for(T t:a)
        if(ans.empty() || t!=ans.back())
            ans.push_back(t);
    return ans;
}



void solve();
int main(){
    GLHF;
    int t=1;
    //cin >> t;
    while(t--)
        solve();
}
bool ok(string s){
    int n=s.size();
    vi pref(n);

    for(int i=0; i<n; i++)
        pref[i]=(i?pref[i-1]:0)+(s[i]=='L'?1:-1);

    auto sum=[&](int l,int r){
        return pref[r]-(l?pref[l-1]:0);
    };
    for(int i=0; i<n; i++)
        for(int j=i+2; j<n; j++){
            if(abs(sum(i,j))>2)return 0;
        }
    return 1;
}

ll calc(string t){
    int n=t.size(),ans=0;
    vector<string>v;
    for(int i=0; i<(1<<n); i++){
        string s;
        for(int j=0; j<n; j++)
            if(i&(1<<j))
                s+='L';
            else
                s+='P';
       if(s<=t && ok(s))
           v.pb(s),ans++;
    }
    sort(all(v));
    //print(v)
    cout.flush();
    return ans;
}
void solve() {
    ll n,mod;
    cin >> n >> mod;
    string s;
    cin >> s;
    out(calc(s)%mod)
    ll ans=0;//how many are lexic. smaller than s

    vector<vvl>dp(n+1,vvl(2,vl(2)));

    dp[1][0][1]=dp[1][1][0]=2;
    dp[1][0][0]=dp[1][1][1]=1;

    for(int i=2; i<=n; i++){
        for(int c1=0; c1<2; c1++)
            for(int c2=0; c2<2; c2++){
                if(c1!=c2)
                    dp[i][c1][c2]=(dp[i-1][c2][c2]+dp[i-1][c2][c2^1])%mod;
                else
                    dp[i][c1][c2]=dp[i-1][c2][c2^1]%mod;
            }
    }

    // L < P !!!

    for(int i=1; i<n; i++){//i is tie-breaker
        if(s[i]=='L')continue;
        ans=(ans+dp[n-i-1][1][(s[i-1]=='L')])%mod;
    }
    cout << calc(s) << endl;
    if(s[0]=='P') {
        ans=(ans+dp[n-2][1][0])%mod;
        ans=(ans+dp[n-2][1][1])%mod;
    }
    ans=(ans+1)%mod;
    out(ans)
}
/*
 12
 100000000
 LPLLPLPPLPLL
 */

Compilation message (stderr)

linear_garden.cpp: In function 'void usaco(std::string)':
linear_garden.cpp:47:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |     freopen(FIN, "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~
linear_garden.cpp:48:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   48 |     freopen(FOUT, "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~

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