Submission #1125444

#	Time	Username	Problem	Language	Result	Execution time	Memory
1125444		ljtunas	Alternating Heights (CCO22_day1problem1)	C++17	25 / 25	314 ms	27988 KiB

Main

// author : anhtun_hi , nqg
// 25-26.12.2024

#include <bits/stdc++.h>
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define reset(h, v)    memset(h, v, sizeof h)
#define Forv(i, a)     for(auto& i : a)
#define For(i, a, b)   for(int i = a; i <= b; ++i)
#define Ford(i, a, b)  for(int i = a; i >= b; --i)
#define c_bit(i)     __builtin_popcountll(i)
#define Bit(mask, i)    ((mask >> i) & 1LL)
#define onbit(mask, i)  ((mask) bitor (1LL << i))
#define offbit(mask, i) ((mask) &~ (1LL << i))
#define Log2(x) (63 - __builtin_clzll(x))
#define TIME (1.0 * clock() / CLOCKS_PER_SEC)
using namespace std;

using ll = long long;
using ii = pair<ll, ll>;
using db = long double;
using ull = unsigned long long;

namespace std {
    template <typename T, int D>
    struct _vector : public vector <_vector <T, D - 1>> {
        static_assert(D >= 1, "Dimension must be positive!");
        template <typename... Args>
        _vector(int n = 0, Args... args) : vector <_vector <T, D - 1>> (n, _vector <T, D - 1> (args...)) {}
    };
    template <typename T> struct _vector <T, 1> : public vector <T> {
        _vector(int n = 0, const T& val = T()) : vector <T> (n, val) {}
    };
    template <class A, class B> bool minimize(A &a, B b){return a > b ? a = b, true : false;}
    template <class A, class B> bool maximize(A &a, B b){return a < b ? a = b, true : false;}
}
const int dx[] = {0, 0, +1, -1}, dy[] = {-1, +1, 0, 0}, LOG = 20, base = 311, inf = 1e9 + 5;
const int MAXN = 1e6 + 5;
const  ll  mod = 1e9 + 7;
const  ll   oo = 1e18;

//#define int long long

int n, k, q, a[MAXN], num[MAXN], low[MAXN], timedfs = 0, tpltm = 0; bool vs[MAXN];
vector<int> g[MAXN];

bool chutrinh = false;

stack<int> st;
void dfs_tarjan(int u) {
    num[u] = low[u] = ++timedfs;
    st.push(u);
    for(int v : g[u]) {
        if (num[v] == 0) dfs_tarjan(v), low[u] = min(low[u], low[v]);
        else low[u] = min(low[u], num[v]);
    }
    if (low[u] == num[u]) {
        int v = 0;
        ++tpltm;
        while (v != u) {
            v = st.top(), st.pop();
            num[v] = low[v] = +inf;
        }
    }
}

bool check(int l, int r){
    For(i, 1, k) g[i].clear();
    timedfs = 0, tpltm = 0;
    For(i, l, r - 1){
        if (a[i] == a[i + 1]) return false;
        if ((i - l) & 1){
            g[a[i]].push_back(a[i + 1]);
        } else {
            g[a[i + 1]].push_back(a[i]);
        }
    }
    fill(num + 1, num + k + 1, 0);
    fill(low + 1, low + k + 1, 0);
    chutrinh = false; while(st.size()) st.pop();
    For(i, 1, k) if (!num[i]) dfs_tarjan(i);
    return tpltm == k;
}

int mx[MAXN];

void Solve() {
    cin >> n >> k >> q;
    For(i, 1, n) cin >> a[i];
    for (int i = 1, j = 0; i <= n; ++i){
        while (j < n && check(i, j + 1)) ++j;
        mx[i] = j; //cerr << j << '\n';
    }
//    cout << check(2, 6) << '\n';
    while(q--){
        int l, r;
        cin >> l >> r;
        if (mx[l] < r) cout << "NO\n";
        else cout << "YES\n";
    }
}

signed main() {
    cin.tie(0) -> sync_with_stdio(0);
    if(fopen("a.inp", "r")) {
        freopen("a.inp", "r", stdin);
        freopen("a.out", "w", stdout);
    }

    int t = 1;
//    cin >> t;
    while(t --) Solve();
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:107:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  107 |         freopen("a.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
Main.cpp:108:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  108 |         freopen("a.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 6 / 6
• Subtask 3: 7 / 7
• Subtask 4: 8 / 8