Submission #1123576

#	Time	Username	Problem	Language	Result	Execution time	Memory
1123576		kh0i	Linear Garden (IOI08_linear_garden)	C++17	100 / 100	801 ms	1504 KiB

linear_garden

#include "bits/stdc++.h"
using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...)
#endif

using ll = long long;
using pii = pair<int, int>;

#define F first
#define S second
#define sz(x) (int)((x).size())
#define all(x) (x).begin(), (x).end()

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll get_rand(ll l, ll r) {
    assert(l <= r);
    return uniform_int_distribution<ll> (l, r)(rng);
}

const int N = 1e6;

int n;
ll m;
string s;
ll f[2][3][3][5][2];

void solve(){
    cin >> n >> m;
    cin >> s;

    for(int i = n; i >= 0; --i){
        for(int mn = -2; mn <= 0; ++mn){
            for(int mx = 0; mx <= 2; ++mx){
                if(mx - mn > 2)
                    continue;
                for(int sum = -2; sum <= 2; ++sum){
                    for(int lower = 0; lower <= 1; ++lower){
                        ll &cur = f[i & 1][mn + 2][mx][sum + 2][lower];
                        if(i == n){
                            cur = 1;
                            continue;
                        }
                        if(sum + 1 <= 2 and max(mx, sum + 1) - mn <= 2){
                            cur += f[i & 1 ^ 1][mn + 2][max(mx, sum + 1)][sum + 1 + 2][lower | (s[i] == 'P')];
                            cur %= m;
                        }
                        if(lower or s[i] == 'P'){
                            if(sum - 1 >= -2 and mx - min(sum - 1, mn) <= 2){
                                cur += f[i & 1 ^ 1][min(sum - 1, mn) + 2][mx][sum - 1 + 2][lower];
                                cur %= m;
                            }
                        }
                        // debug(i, mn, mx, sum, lower, cur);
                    }
                }
            }
        }
        memset(f[i & 1 ^ 1], 0, sizeof(f[i & 1 ^ 1]));
    }
    cout << f[0][2][0][2][0];
}

int32_t main() {
    cin.tie(nullptr)->sync_with_stdio(0);
    #define task "troll"
    if(fopen(task".inp", "r")){
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int test = 1;
//    cin >> test;
    for(int i = 1; i <= test; ++i){
//        cout << "Case #" << i << ": ";
        solve();
    }
    #ifdef LOCAL
        cerr << "\n[Time]: " << 1000.0 * clock() / CLOCKS_PER_SEC << " ms.\n";
    #endif
    return 0;
}

Compilation message (stderr)

linear_garden.cpp: In function 'int32_t main()':
linear_garden.cpp:71:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
linear_garden.cpp:72:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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