Submission #545923

#	Time	Username	Problem	Language	Result	Execution time	Memory
545923		SmolBrain	Linear Garden (IOI08_linear_garden)	C++17	95 / 100	1534 ms	9740 KiB

linear_garden

// Om Namah Shivaya
// GM in 119 days

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define endl '\n'
#define pb push_back
#define conts continue
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "YES" << endl
#define no cout << "NO" << endl
#define ff first
#define ss second
#define ceil2(x,y) ((x+y-1) / (y))
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#ifndef ONLINE_JUDGE
#define debug(x) cout << #x <<" = "; print(x); cout << endl
#else
#define debug(x)
#endif

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

bool iseven(ll n) {if ((n & 1) == 0) return true; return false;}

void print(ll t) {cout << t;}
void print(int t) {cout << t;}
void print(string t) {cout << t;}
void print(char t) {cout << t;}
void print(double t) {cout << t;}
void print(ld t) {cout << t;}

template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(pair <T, V> p) {cout << "{"; print(p.ff); cout << ","; print(p.ss); cout << "}";}
template <class T> void print(vector <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(set <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(multiset <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T, class V> void print(map <T, V> v) {cout << "[ "; for (auto i : v) {print(i); cout << " ";} cout << "]";}
template<typename T> void amin(T &a, T b) { a = min(a, b); }
template<typename T> void amax(T &a, T b) { a = max(a, b); }

void usaco(string filename) {
    freopen((filename + ".in").c_str(), "r", stdin);
    freopen((filename + ".out").c_str(), "w", stdout);
}

const int MOD = 1e9 + 7;
const int maxn = 1e5 + 5;
const int inf1 = 1e9 + 5;
const ll inf2 = ll(1e18) + 5;

void solve(int test_case)
{
    int n, m; cin >> n >> m;
    string s; cin >> s;

    vector<pii> val(n);
    int l = 0, p = 0;

    rep(i, n) {
        val[i] = {l, p};
        if (s[i] == 'L') {
            l++;
            p = max(p - 1, 0);
        }
        else {
            l = max(l - 1, 0);
            p++;
        }
    }

    int dp1[2][3][3][3][3], dp2[2][3][3][3][3];
    memset(dp1, 0, sizeof dp1);
    memset(dp2, 0, sizeof dp2);

    dp1[0][1][0][1][0] = 1;
    dp1[1][0][1][0][1] = 1;
    ll ans = 0;

    rev(i, n - 1, 0) {
        l = val[i].ff, p = val[i].ss;

        if (s[i] == 'P') {
            rep(mxprel, 3) {
                rep(mxprep, 3) {
                    rep(mxl, 3) {
                        rep(mxp, 3) {
                            if (mxprel + l > 2) conts;
                            if (mxprep + p > 2) conts;

                            ans += dp1[0][mxprel][mxprep][mxl][mxp];
                            ans %= m;
                        }
                    }
                }
            }
        }

        if (i == 0) break;

        rep(j, 2) {
            rep(mxprel, 3) {
                rep(mxprep, 3) {
                    rep(mxl, 3) {
                        rep(mxp, 3) {
                            ll val = dp1[j][mxprel][mxprep][mxl][mxp];

                            // place l
                            if (mxprel + 1 <= 2) {
                                dp2[0][mxprel + 1][max(mxprep - 1, 0)][max(mxl, mxprel + 1)][mxp] += val;
                                dp2[0][mxprel + 1][max(mxprep - 1, 0)][max(mxl, mxprel + 1)][mxp] %= m;
                            }

                            // place p
                            if (mxprep + 1 <= 2) {
                                dp2[1][max(mxprel - 1, 0)][mxprep + 1][mxl][max(mxp, mxprep + 1)] += val;
                                dp2[1][max(mxprel - 1, 0)][mxprep + 1][mxl][max(mxp, mxprep + 1)] %= m;
                            }
                        }
                    }
                }
            }
        }

        rep(j, 2) {
            rep(mxprel, 3) {
                rep(mxprep, 3) {
                    rep(mxl, 3) {
                        rep(mxp, 3) {
                            dp1[j][mxprel][mxprep][mxl][mxp] = dp2[j][mxprel][mxprep][mxl][mxp];
                            dp2[j][mxprel][mxprep][mxl][mxp] = 0;
                        }
                    }
                }
            }
        }
    }

    ans++;
    ans %= m;

    cout << ans << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;
    rep1(i, t) {
        solve(i);
    }

    return 0;
}

Compilation message (stderr)

linear_garden.cpp: In function 'void usaco(std::string)':
linear_garden.cpp:64:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |     freopen((filename + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
linear_garden.cpp:65:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |     freopen((filename + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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