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답안 #1108010

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1108010 2024-11-02T14:53:46 Z atom Lampice (COCI19_lampice) C++17
110 / 110
 1716 ms 45896 KB 
    #include <bits/stdc++.h>
    using namespace std;
    #define task ""
    #define all(x) (x).begin(), (x).end()
    #define rall(x) (x).rbegin(), (x).rend()
     
    const int MAX = 50005;
    int n, k;
    char a[MAX];
    int sz[MAX];
    bool rem[MAX];
    vector<int> adj[MAX];
     
    const int MOD = 1e9 + 7;
    const int BASE = 256;
    int pw[MAX];
     
    int dfsSZ(int u, int p) {
        sz[u] = 1;
        for (int v: adj[u]) if (v != p && !rem[v]) {
            sz[u] += dfsSZ(v, u);
        }
        return sz[u];
    }
     
    int findCentroid(int u, int p, int n) {
        for (int v: adj[u]) if (v != p && !rem[v]) {
            if (2 * sz[v] > n)
                return findCentroid(v, u, n);
        }
        return u;
    }
     
    int h[MAX];
    int maxHigh;
    int hashU[MAX];
    int hashD[MAX];
    int value[MAX];
    int nNode, node[MAX];
    map<int, bool> mp[MAX];
     
    void add(int u, int p, bool &found) {
        h[u] = h[p] + 1;
        if (h[u] + 1 > k) return;
        maxHigh = max(maxHigh, h[u]);
        hashU[u] = (1LL * hashU[p] * BASE + (a[u] - 'a' + 1)) % MOD;
        hashD[u] = (hashD[p] + 1LL * pw[h[u]] * (a[u] - 'a' + 1)) % MOD;
        int need = (1LL * pw[k - h[u] - 1] * hashD[u] - hashU[u] + MOD) % MOD;
        if (mp[k - h[u] - 1].find(need) != mp[k - h[u] - 1].end()) {
            found = true;
            return;
        }
        if (h[u] + 1 == k && hashD[u] == (hashU[u] + 1LL * pw[h[u]] * (a[u] - 'a' + 1)) % MOD) {
            found = true;
            return;
        }
        node[++nNode] = u; value[u] = need;
        for (int v: adj[u]) if (v != p && !rem[v]) {
            add(v, u, found);
            if (found) return;
        }
    }
     
    void solve(int u, int p, bool &found) {
        int n = dfsSZ(u, p), c = findCentroid(u, p, n); rem[c] = true;
     
        h[c] = 0;
        nNode = 0;
        maxHigh = 0;
        hashU[c] = 0;
        hashD[c] = a[c] - 'a' + 1;
        for (int v: adj[c]) if (v != p && !rem[v]) {
            add(v, c, found);
            if (found) return;
            while (nNode > 0) {
                int u = node[nNode--];
                mp[h[u]][value[u]] = 1;
            }
        }
        for (int i = 0; i <= maxHigh; ++i) {
            mp[i].clear();
        }
     
        for (int v: adj[c]) if (v != p && !rem[v]) {
            solve(v, c, found);
            if (found) return;
        }
    }
     
    bool ok(int x) {
        memset(rem, false, sizeof rem);
        bool found = false; k = x;
        solve(1, 0, found);
        return found;
    }
     
    int main() {
    	ios_base::sync_with_stdio(false); cin.tie(nullptr);
     
    	if (fopen(task".inp", "r")) {
    		freopen(task".inp", "r",  stdin);
    		freopen(task".out", "w", stdout);
    	}
     
        cin >> n >> (a + 1); pw[0] = 1; for (int i = 1; i <= n; ++i) pw[i] = 1LL * pw[i - 1] * BASE % MOD;
        for (int i = 1; i <= n - 1; ++i) {
            int u, v; cin >> u >> v;
            adj[u].push_back(v);
            adj[v].push_back(u);
        }
        int ans = 1;
        for (int i = 0; i < 2; ++i) {
            int l = 0, r = n / 2 + 1;
            while (r - l > 1) {
                int mid = l + r >> 1;
                if (ok(i + 2 * mid)) l = mid; else r = mid;
            }
            ans = max(ans, i + 2 * l);
        }
        cout << ans;
     
    	return 0;
    }

Compilation message

lampice.cpp: In function 'int main()':
lampice.cpp:115:29: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  115 |                 int mid = l + r >> 1;
      |                           ~~^~~
lampice.cpp:101:14: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  101 |       freopen(task".inp", "r",  stdin);
      |       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
lampice.cpp:102:14: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  102 |       freopen(task".out", "w", stdout);
      |       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
17.0 / 17.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 5200 KB Output is correct
2 Correct 5 ms 5200 KB Output is correct
3 Correct 16 ms 5200 KB Output is correct
4 Correct 14 ms 5200 KB Output is correct
5 Correct 1 ms 5164 KB Output is correct
6 Correct 2 ms 5200 KB Output is correct
7 Correct 1 ms 5200 KB Output is correct

Subtask #2
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 596 ms 11344 KB Output is correct
2 Correct 625 ms 13464 KB Output is correct
3 Correct 415 ms 24164 KB Output is correct
4 Correct 510 ms 23860 KB Output is correct
5 Correct 811 ms 14160 KB Output is correct
6 Correct 193 ms 45896 KB Output is correct

Subtask #3
31.0 / 31.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1327 ms 10064 KB Output is correct
2 Correct 1716 ms 10480 KB Output is correct
3 Correct 1491 ms 10412 KB Output is correct
4 Correct 1231 ms 11388 KB Output is correct
5 Correct 1133 ms 15080 KB Output is correct
6 Correct 1056 ms 9652 KB Output is correct

Subtask #4
37.0 / 37.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 5200 KB Output is correct
2 Correct 5 ms 5200 KB Output is correct
3 Correct 16 ms 5200 KB Output is correct
4 Correct 14 ms 5200 KB Output is correct
5 Correct 1 ms 5164 KB Output is correct
6 Correct 2 ms 5200 KB Output is correct
7 Correct 1 ms 5200 KB Output is correct
8 Correct 596 ms 11344 KB Output is correct
9 Correct 625 ms 13464 KB Output is correct
10 Correct 415 ms 24164 KB Output is correct
11 Correct 510 ms 23860 KB Output is correct
12 Correct 811 ms 14160 KB Output is correct
13 Correct 193 ms 45896 KB Output is correct
14 Correct 1327 ms 10064 KB Output is correct
15 Correct 1716 ms 10480 KB Output is correct
16 Correct 1491 ms 10412 KB Output is correct
17 Correct 1231 ms 11388 KB Output is correct
18 Correct 1133 ms 15080 KB Output is correct
19 Correct 1056 ms 9652 KB Output is correct
20 Correct 1035 ms 9672 KB Output is correct
21 Correct 1364 ms 11368 KB Output is correct
22 Correct 1607 ms 10540 KB Output is correct
23 Correct 357 ms 7752 KB Output is correct
24 Correct 1049 ms 9064 KB Output is correct
25 Correct 968 ms 8972 KB Output is correct
26 Correct 1356 ms 10568 KB Output is correct
27 Correct 1677 ms 9812 KB Output is correct
28 Correct 700 ms 7752 KB Output is correct
29 Correct 783 ms 7760 KB Output is correct
30 Correct 954 ms 10056 KB Output is correct
31 Correct 770 ms 8380 KB Output is correct
32 Correct 875 ms 13128 KB Output is correct
33 Correct 935 ms 9916 KB Output is correct