oj.uz

답안 #997275

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
997275 2024-06-12T00:44:09 Z Gilgamesh Love Polygon (BOI18_polygon) C++17
75 / 100
 317 ms 37072 KB 
#include <iostream>
#include <algorithm>
#include <utility>
#include <vector>
#include <stack>
#include <map>
#include <queue>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <cstring>
#include <cmath>
#include <functional>
#include <cassert>
#include <iomanip>
#include <numeric>
#include <bitset>
#include <sstream>
#include <chrono>
#include <random>
 
#define ff first
#define ss second
#define PB push_back
#define sz(x) int(x.size())
#define rsz resize
#define fch(xxx, yyy) for (auto xxx : yyy) // abusive notation
#define all(x) (x).begin(),(x).end()
#define eps 1e-9
 
// more abusive notation (use at your own risk):
//#define int ll
 
using namespace std;
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vll = vector<ll>;
 
// debugging
void __print(int x) {std::cerr << x;}
void __print(ll x) {std::cerr << x;} /* remember to uncomment this when not using THE MACRO */
void __print(unsigned x) {std::cerr << x;}
void __print(ull x) {std::cerr << x;}
void __print(float x) {std::cerr << x;}
void __print(double x) {std::cerr << x;}
void __print(ld x) {std::cerr << x;}
void __print(char x) {std::cerr << '\'' << x << '\'';}
void __print(const char *x) {std::cerr << '\"' << x << '\"';}
void __print(const string& x) {std::cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V> void __print(const pair<T, V> &x) {std::cerr << '{'; __print(x.ff); std::cerr << ", "; __print(x.ss); std::cerr << '}';}
template<typename T> void __print(const T& x) {int f = 0; std::cerr << '{'; for (auto &i: x) std::cerr << (f++ ? ", " : ""), __print(i); std::cerr << "}";}
void _print() {std::cerr << "]\n";}
template <typename T, typename... V> void _print(T t, V... v) {__print(t); if (sizeof...(v)) std::cerr << ", "; _print(v...);}
void println() {std::cerr << ">--------------------<" << endl;}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif
 
// templates
template <class T> bool ckmin(T &a, const T &b) {return b<a ? a = b, 1 : 0;}
template <class T> bool ckmax(T &a, const T &b) {return b>a ? a = b, 1 : 0;}
template <class T> using gr = greater<T>;
template <class T> using vc = vector<T>;
template <class T> using p_q = priority_queue<T>;
template <class T> using pqg = priority_queue<T, vc<T>, gr<T>>;
template <class T1, class T2> using pr = pair<T1, T2>;
mt19937_64 rng_ll(chrono::steady_clock::now().time_since_epoch().count());
int rng(int M) {return (int)(rng_ll()%M);} /*returns any random number in [0, M) */
 
// const variables
constexpr int INF = (int)2e9;
constexpr int MOD = 998244353;
constexpr ll LL_INF = (ll)3e18;
constexpr int mod = (int)1e9 + 7;
constexpr ll inverse = 500000004LL; // inverse of 2 modulo 1e9 + 7
 
void setIO(const string& str) {// fast input/output
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    if (str.empty()) return;
    freopen((str + ".in").c_str(), "r", stdin);
    freopen((str + ".out").c_str(), "w", stdout);
}
 
// f: f[u] = the one u loves
int N, cnt = 1;
map<string, int> mp; // mapping strings to integer indices
vc<vi> adj; // for each v, keep track of all u such that f[u] = v
vc<vi> $, comps; // $ is the undirected version of the graph
// comps keeps track of the vertices in each component
vi dp[2], vst, f, cc;
// cc[v] = component that v is in
 
void dfs(int v) {
    dp[0][v] = 0, dp[1][v] = 1;
    vst[v] = 1;
    vi children; // children of v
    fch(u, adj[v]) if (!vst[u]) {
            dfs(u);
            children.PB(u);
            dp[1][v] += dp[0][u];
        }
    if (sz(children) == 0) return;
    int C = sz(children);
    vi psum(C), ssum(C);
    for (int i = 0; i < C; ++i) {
        psum[i] = (i > 0 ? psum[i - 1] : 0) + dp[0][children[i]];
    }
    for (int i = C-1; i >= 0; --i) {
        ssum[i] = (i < C - 1 ? ssum[i + 1] : 0) + dp[0][children[i]];
    }
    for (int i = 0; i < C; ++i) {
        ckmax(dp[0][v], dp[1][children[i]] + (i > 0 ? psum[i - 1] : 0) + (i < C - 1 ? ssum[i + 1] : 0));
    }
}
 
void undo(int v) {
    for (int i = 0; i < sz(comps[cc[v]]); ++i) { // resetting all visited values in component to 0
        vst[comps[cc[v]][i]] = 0;
    }
}
 
void why_not(int v) {
    for (int i = 0; i < sz(comps[cc[v]]); ++i) { // set them all to 1
        vst[comps[cc[v]][i]] = 1;
    }
}
 
void dfs1(int v) {
    fch(u, $[v]) if (cc[u] != cc[v]) { // finding connected components
            cc[u] = cc[v];
            dfs1(u);
        }
}
 
signed main() { // TIME YOURSELF !!!
    setIO("");
    cin >> N;
    if (N & 1) {
        cout << "-1\n";
        return 0;
    }
    adj.rsz(N+1), dp[0].rsz(N+1, 0), dp[1].rsz(N+1, 1), vst.rsz(N+1), f.rsz(N+1), cc.rsz(N+1, -1), comps.rsz(N+1);
    $.rsz(N + 1);
    for (int i = 0; i < N; ++i) {
        string a, b;
        cin >> a >> b;
        if (mp[a] == 0) mp[a] = cnt++;
        if (mp[b] == 0) mp[b] = cnt++;
        adj[mp[b]].PB(mp[a]);
        $[mp[b]].PB(mp[a]);
        $[mp[a]].PB(mp[b]);
        f[mp[a]] = mp[b];
    }
    { // finding the connected components
        for (int i = 1; i <= N; ++i) {
            if (cc[i] == -1) {
                cc[i] = i;
                dfs1(i);
            }
        }
        for (int i = 1; i <= N; ++i) {
            comps[cc[i]].PB(i);
        }
    }
    int ans = 0;
    for (int i = 1; i <= N; ++i) {
        if (!vst[i]) {
            int t = f[i], h = f[f[i]]; // find the cycle
            while (t != h) {
                t = f[t];
                h = f[f[h]];
            }
            int L = 1;
            t = f[t];
            while (t != h) {
                L++;
                t = f[t];
            }
            if (L == 1) { // self-loop
                vst[t] = 1;
                dfs(t);
                ans += dp[0][t]; // t cannot be in the set
            } else { // not a self-loop
                int res = 0;
                int s = f[t];
                // 2: (t, f[t]) are not connected
                dfs(t);
                ckmax(res, dp[0][t]);
                undo(t);
                // 1: (t, f[t]) are connected
                if (L > 2) {
                    vst[t] = vst[s] = 1;
                    int temp = t;
                    t = f[s];
                    while (f[t] != temp) {
                        t = f[t];
                    }
                    dfs(t); // do DP over all vertices in the cycle excluding (t, s) and also the
                    // subtrees with each such vertex
                    int sum = dp[0][t];
                    t = temp;
                    // now DFS over all vertices that are not in the cycle but have f[u] = t or s
                    fch(u, adj[t]) if (!vst[u]) {
                            dfs(u);
                            sum += dp[0][u]; // cannot be in the set
                        }
                    fch(u, adj[s]) if (!vst[u]) {
                            dfs(u);
                            sum += dp[0][u]; // cannot be in the set
                        }
                    ckmax(res, sum);
                } else if (L == 2) {
                    vst[t] = vst[s] = 1;
                    int sum = 2;
                    // similar logic here
                    fch(u, adj[t]) if (!vst[u]) {
                            dfs(u);
                            sum += dp[0][u];
                        }
                    fch(u, adj[s]) if (!vst[u]) {
                            dfs(u);
                            sum += dp[0][u];
                        }
                    ckmax(res, sum);
                }
                ans += res;
            }
            why_not(i);
        }
    }
    assert(ans <= N);
    cout << N - ans << '\n';
    return 0;
}
 
// TLE -> TRY NOT USING DEFINE INT LONG LONG
// CE -> CHECK LINE 45
// 5000 * 5000 size matrices are kinda big (potential mle)
// Do something, start simpler

Compilation message

polygon.cpp: In function 'void setIO(const string&)':
polygon.cpp:88:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   88 |     freopen((str + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
polygon.cpp:89:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |     freopen((str + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
21.0 / 21.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 0 ms 348 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 0 ms 344 KB Output is correct
10 Correct 0 ms 464 KB Output is correct
11 Correct 1 ms 348 KB Output is correct
12 Correct 0 ms 348 KB Output is correct
13 Correct 0 ms 348 KB Output is correct
14 Correct 1 ms 348 KB Output is correct
15 Correct 0 ms 344 KB Output is correct

Subtask #2
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 1 ms 344 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 317 ms 35568 KB Output is correct
5 Correct 283 ms 26556 KB Output is correct
6 Correct 302 ms 37072 KB Output is correct
7 Correct 0 ms 344 KB Output is correct

Subtask #3
29.0 / 29.0

# 결과 실행 시간 메모리 Grader output
1 Correct 291 ms 25816 KB Output is correct
2 Correct 273 ms 28072 KB Output is correct
3 Correct 277 ms 28636 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 295 ms 36104 KB Output is correct
6 Correct 274 ms 24932 KB Output is correct
7 Correct 266 ms 24916 KB Output is correct
8 Correct 254 ms 25972 KB Output is correct
9 Correct 246 ms 24528 KB Output is correct
10 Correct 169 ms 24900 KB Output is correct
11 Correct 0 ms 348 KB Output is correct
12 Correct 0 ms 348 KB Output is correct
13 Correct 0 ms 348 KB Output is correct
14 Correct 0 ms 348 KB Output is correct

Subtask #4
0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 0 ms 348 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 0 ms 344 KB Output is correct
10 Correct 0 ms 464 KB Output is correct
11 Correct 1 ms 348 KB Output is correct
12 Correct 0 ms 348 KB Output is correct
13 Correct 0 ms 348 KB Output is correct
14 Correct 1 ms 348 KB Output is correct
15 Correct 0 ms 344 KB Output is correct
16 Correct 0 ms 344 KB Output is correct
17 Correct 1 ms 344 KB Output is correct
18 Correct 0 ms 348 KB Output is correct
19 Correct 317 ms 35568 KB Output is correct
20 Correct 283 ms 26556 KB Output is correct
21 Correct 302 ms 37072 KB Output is correct
22 Correct 0 ms 344 KB Output is correct
23 Correct 291 ms 25816 KB Output is correct
24 Correct 273 ms 28072 KB Output is correct
25 Correct 277 ms 28636 KB Output is correct
26 Correct 0 ms 348 KB Output is correct
27 Correct 295 ms 36104 KB Output is correct
28 Correct 274 ms 24932 KB Output is correct
29 Correct 266 ms 24916 KB Output is correct
30 Correct 254 ms 25972 KB Output is correct
31 Correct 246 ms 24528 KB Output is correct
32 Correct 169 ms 24900 KB Output is correct
33 Correct 0 ms 348 KB Output is correct
34 Correct 0 ms 348 KB Output is correct
35 Correct 0 ms 348 KB Output is correct
36 Correct 0 ms 348 KB Output is correct
37 Correct 299 ms 25880 KB Output is correct
38 Incorrect 314 ms 26696 KB Output isn't correct
39 Halted 0 ms 0 KB -