oj.uz

Submission #997300

# Submission time Handle Problem Language Result Execution time Memory
997300 2024-06-12T03:21:16 Z whatthemomooofun1729 Love Polygon (BOI18_polygon) C++17
100 / 100
 335 ms 36296 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] + 1;
                    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

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 344 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 1 ms 384 KB Output is correct
10 Correct 0 ms 348 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
15 Correct 0 ms 460 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 326 ms 34756 KB Output is correct
5 Correct 292 ms 25604 KB Output is correct
6 Correct 324 ms 36048 KB Output is correct
7 Correct 0 ms 344 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 270 ms 24652 KB Output is correct
2 Correct 311 ms 27380 KB Output is correct
3 Correct 230 ms 27732 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 298 ms 35320 KB Output is correct
6 Correct 283 ms 24016 KB Output is correct
7 Correct 276 ms 23892 KB Output is correct
8 Correct 264 ms 25172 KB Output is correct
9 Correct 252 ms 23744 KB Output is correct
10 Correct 179 ms 24132 KB Output is correct
11 Correct 1 ms 348 KB Output is correct
12 Correct 1 ms 348 KB Output is correct
13 Correct 1 ms 348 KB Output is correct
14 Correct 0 ms 348 KB Output is correct

Subtask #4
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 344 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 1 ms 384 KB Output is correct
10 Correct 0 ms 348 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
15 Correct 0 ms 460 KB Output is correct
16 Correct 0 ms 348 KB Output is correct
17 Correct 0 ms 348 KB Output is correct
18 Correct 0 ms 348 KB Output is correct
19 Correct 326 ms 34756 KB Output is correct
20 Correct 292 ms 25604 KB Output is correct
21 Correct 324 ms 36048 KB Output is correct
22 Correct 0 ms 344 KB Output is correct
23 Correct 270 ms 24652 KB Output is correct
24 Correct 311 ms 27380 KB Output is correct
25 Correct 230 ms 27732 KB Output is correct
26 Correct 0 ms 348 KB Output is correct
27 Correct 298 ms 35320 KB Output is correct
28 Correct 283 ms 24016 KB Output is correct
29 Correct 276 ms 23892 KB Output is correct
30 Correct 264 ms 25172 KB Output is correct
31 Correct 252 ms 23744 KB Output is correct
32 Correct 179 ms 24132 KB Output is correct
33 Correct 1 ms 348 KB Output is correct
34 Correct 1 ms 348 KB Output is correct
35 Correct 1 ms 348 KB Output is correct
36 Correct 0 ms 348 KB Output is correct
37 Correct 297 ms 25172 KB Output is correct
38 Correct 297 ms 25780 KB Output is correct
39 Correct 284 ms 24148 KB Output is correct
40 Correct 286 ms 24020 KB Output is correct
41 Correct 286 ms 23892 KB Output is correct
42 Correct 288 ms 24400 KB Output is correct
43 Correct 288 ms 24272 KB Output is correct
44 Correct 287 ms 24340 KB Output is correct
45 Correct 286 ms 24372 KB Output is correct
46 Correct 303 ms 24272 KB Output is correct
47 Correct 259 ms 23836 KB Output is correct
48 Correct 288 ms 24660 KB Output is correct
49 Correct 335 ms 27208 KB Output is correct
50 Correct 230 ms 27836 KB Output is correct
51 Correct 0 ms 348 KB Output is correct
52 Correct 306 ms 35316 KB Output is correct
53 Correct 274 ms 24020 KB Output is correct
54 Correct 282 ms 23888 KB Output is correct
55 Correct 257 ms 25168 KB Output is correct
56 Correct 250 ms 23632 KB Output is correct
57 Correct 177 ms 24132 KB Output is correct
58 Correct 0 ms 348 KB Output is correct
59 Correct 0 ms 348 KB Output is correct
60 Correct 0 ms 348 KB Output is correct
61 Correct 0 ms 460 KB Output is correct
62 Correct 0 ms 348 KB Output is correct
63 Correct 0 ms 348 KB Output is correct
64 Correct 0 ms 344 KB Output is correct
65 Correct 335 ms 34760 KB Output is correct
66 Correct 297 ms 25680 KB Output is correct
67 Correct 287 ms 36296 KB Output is correct
68 Correct 1 ms 348 KB Output is correct
69 Correct 0 ms 348 KB Output is correct
70 Correct 0 ms 348 KB Output is correct
71 Correct 0 ms 348 KB Output is correct
72 Correct 0 ms 348 KB Output is correct
73 Correct 0 ms 348 KB Output is correct
74 Correct 0 ms 348 KB Output is correct
75 Correct 0 ms 348 KB Output is correct
76 Correct 0 ms 348 KB Output is correct
77 Correct 0 ms 348 KB Output is correct
78 Correct 0 ms 348 KB Output is correct
79 Correct 0 ms 348 KB Output is correct
80 Correct 0 ms 348 KB Output is correct
81 Correct 0 ms 348 KB Output is correct
82 Correct 1 ms 348 KB Output is correct
83 Correct 0 ms 348 KB Output is correct