oj.uz

Submission #856116

# Submission time Handle Problem Language Result Execution time Memory
856116 2023-10-02T17:07:42 Z RiverFlow Love Polygon (BOI18_polygon) C++14
100 / 100
 174 ms 25936 KB 
#include <bits/stdc++.h>

#define nl "\n"
#define no "NO"
#define yes "YES"
#define fi first
#define se second
#define vec vector
#define task "main"
#define _mp make_pair
#define ii pair<int, int>
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define evoid(val) return void(std::cout << val)
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define FOD(i, b, a) for(int i = (b); i >= (a); --i)
#define unq(x) sort(all(x)); x.resize(unique(all(x)) - x.begin())

using namespace std;

template<typename U, typename V> bool maxi(U &a, V b) {
    if (a < b) { a = b; return 1; } return 0;
}
template<typename U, typename V> bool mini(U &a, V b) {
    if (a > b or a == -1) { a = b; return 1; } return 0;
}

const int N = (int)2e5 + 9;
const int mod = (int)1e9 + 7;

void prepare(); void main_code();

int main() {
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    const bool MULTITEST = 0; prepare();
    int num_test = 1; if (MULTITEST) cin >> num_test;
    while (num_test--) { main_code(); }
}

void prepare() {};

int n, g[N], deg[N];

vector<int> adj[N];

stack<int> st;

bool on[N], on_cycle[N], vis[N];

void dfs(int u) {
    st.push(u); vis[u] = 1; on[u] = 1;
    int v = g[u];
    if (!vis[v]) {
        dfs(v);
    }
    if (on[v]) {
        while (st.size()) {
            int k = st.top(); on_cycle[k] = 1;
            st.pop(); on[k] = 0; if (k == v) break ;
        }
    }
    if (sz(st) and st.top() == u) st.pop();
    on[u] = 0;
}

int cnt[N], dp[N][2][2];

void main_code() {
    cin >> n; map<string, int> mp;
    if (n % 2 == 1) evoid(-1);
    for(int i = 1, cnt = 0; i <= n; ++i) {
        string x, y; cin >> x >> y;
        if (mp.find(x) == mp.end()) {
            mp[x] = ++cnt;
        }
        if (mp.find(y) == mp.end()) {
            mp[y] = ++cnt;
        }
        int a = mp[x], b = mp[y];
        g[a] = b;
    }
    FOR(i, 1, n) if (!vis[i]) dfs(i);

    FOR(i, 1, n) {
        ++deg[g[i]];
    }

    queue<int> q;
    int res = 0;
    FOR(i, 1, n) if (deg[i] == 0) {
        q.push(i);
    }
    vec<bool> c(n + 1, 0);
    while (!q.empty()) {
        int u = q.front(); q.pop();
        --deg[g[u]]; if (deg[g[u]] == 0) q.push(g[u]);
        if (!c[u]) {
            if (on_cycle[g[u]]) {
                ++cnt[g[u]];
                continue ;
            }
            ++res; if (!c[g[u]] and on_cycle[g[u]] == 0) c[g[u]] = 1;
        }
    }
//    FOR(i, 1, n) cout << c[i] << ' '; cout << nl << res << nl;
//    FOR(i, 1, n) cout << cnt[i] << ' '; cout << nl;
    vec<bool> mark(n + 1, 0);
    FOR(i, 1, n) if (on_cycle[i] and !mark[i]) {
        vec<int> cy;
        cy.push_back(i);
        for(int j = g[i]; j != i; j = g[j]) {
            cy.push_back(j);
        }
        for(int k : cy) {
            if (cnt[k] > 1) {
                res += cnt[k] - 1;
                cnt[k] = 1;
            }
            mark[k] = 1;
        }
        if (sz(cy) == 1) {
            ++res; continue ;
        }
        if (sz(cy) == 2) {
            for(int k : cy) res += cnt[k];
            continue ;
        }
//        for(int k : cy) cout << k << ' '; cout << nl;

        int m = sz(cy);

        FOR(i, 0, m) FOR(j, 0, 1) FOR(k, 0, 1) dp[i][j][k] = n;

        dp[0][0][0] = 1;
        dp[0][0][1] = cnt[ cy[0] ];
        dp[0][1][0] = cnt[ cy[0] ] + 1;

        FOR(i, 0, m - 3) FOR(j, 0, 1) FOR(k, 0, 1) {
            if (k == 0) {
                // no match (i, i + 1)
                mini(dp[i + 1][j][0], dp[i][j][k] + 1);
                mini(dp[i + 1][j][1], dp[i][j][k] + cnt[ cy[i + 1] ]);
            } else {
                mini(dp[i + 1][j][0], dp[i][j][k] + cnt[ cy[i + 1] ] + 1);
            }
        }

        // match (0, m - 1)
        mini(dp[m - 1][1][1], dp[m - 2][1][0] + cnt[ cy[m - 1] ]);

        // match (m - 1, m - 2)
        mini(dp[m - 1][0][0], dp[m - 2][0][1] + cnt[ cy[m - 1] ] + 1);

        // match (m - 1, it'child)
        mini(dp[m - 1][0][0], dp[m - 2][0][0] + 1);

        int l = n; FOR(j, 0, 1) FOR(k, 0, 1) l = min(l, dp[m - 1][j][k]);

        res += l;
    }
    cout << res;
}


/*     Let the river flows naturally     */

Compilation message

polygon.cpp: In function 'int main()':
polygon.cpp:36:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
polygon.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Correct 1 ms 6492 KB Output is correct
4 Correct 1 ms 6744 KB Output is correct
5 Correct 1 ms 6492 KB Output is correct
6 Correct 1 ms 6492 KB Output is correct
7 Correct 1 ms 6624 KB Output is correct
8 Correct 1 ms 6492 KB Output is correct
9 Correct 1 ms 6492 KB Output is correct
10 Correct 2 ms 6492 KB Output is correct
11 Correct 1 ms 6492 KB Output is correct
12 Correct 1 ms 6492 KB Output is correct
13 Correct 1 ms 6492 KB Output is correct
14 Correct 1 ms 6492 KB Output is correct
15 Correct 1 ms 6492 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 1 ms 6616 KB Output is correct
3 Correct 1 ms 6492 KB Output is correct
4 Correct 168 ms 24144 KB Output is correct
5 Correct 139 ms 15824 KB Output is correct
6 Correct 155 ms 25200 KB Output is correct
7 Correct 1 ms 6492 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 141 ms 16208 KB Output is correct
2 Correct 137 ms 16724 KB Output is correct
3 Correct 134 ms 15880 KB Output is correct
4 Correct 2 ms 6488 KB Output is correct
5 Correct 135 ms 18260 KB Output is correct
6 Correct 129 ms 15952 KB Output is correct
7 Correct 174 ms 16564 KB Output is correct
8 Correct 127 ms 16344 KB Output is correct
9 Correct 125 ms 15952 KB Output is correct
10 Correct 107 ms 16016 KB Output is correct
11 Correct 1 ms 6488 KB Output is correct
12 Correct 1 ms 6488 KB Output is correct
13 Correct 1 ms 6488 KB Output is correct
14 Correct 1 ms 6488 KB Output is correct

Subtask #4
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Correct 1 ms 6492 KB Output is correct
4 Correct 1 ms 6744 KB Output is correct
5 Correct 1 ms 6492 KB Output is correct
6 Correct 1 ms 6492 KB Output is correct
7 Correct 1 ms 6624 KB Output is correct
8 Correct 1 ms 6492 KB Output is correct
9 Correct 1 ms 6492 KB Output is correct
10 Correct 2 ms 6492 KB Output is correct
11 Correct 1 ms 6492 KB Output is correct
12 Correct 1 ms 6492 KB Output is correct
13 Correct 1 ms 6492 KB Output is correct
14 Correct 1 ms 6492 KB Output is correct
15 Correct 1 ms 6492 KB Output is correct
16 Correct 1 ms 6492 KB Output is correct
17 Correct 1 ms 6616 KB Output is correct
18 Correct 1 ms 6492 KB Output is correct
19 Correct 168 ms 24144 KB Output is correct
20 Correct 139 ms 15824 KB Output is correct
21 Correct 155 ms 25200 KB Output is correct
22 Correct 1 ms 6492 KB Output is correct
23 Correct 141 ms 16208 KB Output is correct
24 Correct 137 ms 16724 KB Output is correct
25 Correct 134 ms 15880 KB Output is correct
26 Correct 2 ms 6488 KB Output is correct
27 Correct 135 ms 18260 KB Output is correct
28 Correct 129 ms 15952 KB Output is correct
29 Correct 174 ms 16564 KB Output is correct
30 Correct 127 ms 16344 KB Output is correct
31 Correct 125 ms 15952 KB Output is correct
32 Correct 107 ms 16016 KB Output is correct
33 Correct 1 ms 6488 KB Output is correct
34 Correct 1 ms 6488 KB Output is correct
35 Correct 1 ms 6488 KB Output is correct
36 Correct 1 ms 6488 KB Output is correct
37 Correct 146 ms 16192 KB Output is correct
38 Correct 147 ms 19796 KB Output is correct
39 Correct 145 ms 17492 KB Output is correct
40 Correct 148 ms 17104 KB Output is correct
41 Correct 141 ms 16976 KB Output is correct
42 Correct 153 ms 16980 KB Output is correct
43 Correct 140 ms 17152 KB Output is correct
44 Correct 129 ms 17076 KB Output is correct
45 Correct 131 ms 17120 KB Output is correct
46 Correct 133 ms 17156 KB Output is correct
47 Correct 126 ms 17128 KB Output is correct
48 Correct 140 ms 17200 KB Output is correct
49 Correct 153 ms 17728 KB Output is correct
50 Correct 123 ms 16724 KB Output is correct
51 Correct 1 ms 6488 KB Output is correct
52 Correct 140 ms 19024 KB Output is correct
53 Correct 132 ms 16680 KB Output is correct
54 Correct 136 ms 17212 KB Output is correct
55 Correct 129 ms 17328 KB Output is correct
56 Correct 144 ms 16976 KB Output is correct
57 Correct 102 ms 16980 KB Output is correct
58 Correct 1 ms 6492 KB Output is correct
59 Correct 1 ms 6492 KB Output is correct
60 Correct 1 ms 6492 KB Output is correct
61 Correct 1 ms 6492 KB Output is correct
62 Correct 1 ms 6488 KB Output is correct
63 Correct 1 ms 6488 KB Output is correct
64 Correct 1 ms 6492 KB Output is correct
65 Correct 143 ms 25048 KB Output is correct
66 Correct 133 ms 16616 KB Output is correct
67 Correct 165 ms 25936 KB Output is correct
68 Correct 1 ms 6492 KB Output is correct
69 Correct 1 ms 6492 KB Output is correct
70 Correct 1 ms 6492 KB Output is correct
71 Correct 1 ms 6488 KB Output is correct
72 Correct 1 ms 6492 KB Output is correct
73 Correct 2 ms 6492 KB Output is correct
74 Correct 1 ms 6544 KB Output is correct
75 Correct 1 ms 6492 KB Output is correct
76 Correct 1 ms 6616 KB Output is correct
77 Correct 1 ms 6492 KB Output is correct
78 Correct 1 ms 6492 KB Output is correct
79 Correct 1 ms 6492 KB Output is correct
80 Correct 1 ms 6492 KB Output is correct
81 Correct 1 ms 6492 KB Output is correct
82 Correct 1 ms 6616 KB Output is correct
83 Correct 1 ms 6492 KB Output is correct