Submission #967014

#	Time	Username	Problem	Language	Result	Execution time	Memory
967014		blackslex	Capital City (JOI20_capital_city)	C++17	100 / 100	239 ms	58448 KiB

capital_city

#include<bits/stdc++.h>

using namespace std;

int n, k, x, y;

int main() {
    scanf("%d %d", &n, &k);
    vector<int> c(n + 5), st(k + 5), ca(k + 5);
    vector<vector<int>> v(n + 5, vector<int>()), v2(k + 5, vector<int>()), rev(k + 5, vector<int>());
    for (int i = 1; i < n; i++) scanf("%d %d", &x, &y), v[x].emplace_back(y), v[y].emplace_back(x);
    for (int i = 1; i <= n; i++) scanf("%d", &c[i]), ca[c[i]]++;
    int t = 0;
    vector<int> sz(n + 5), hv(n + 5), pos(n + 5), tin(n + 5), tout(n + 5);
    function<void(int, int)> dfs = [&] (int cur, int par) {
        tin[cur] = ++t; pos[t] = cur; sz[cur] = 1;
        for (auto &e: v[cur]) {
            if (par == e) continue;
            dfs(e, cur); sz[cur] += sz[e];
            if (sz[e] > sz[hv[cur]]) hv[cur] = e;
        }
        tout[cur] = t;
    };
    vector<int> col(n + 5), cnt(k + 5);
    auto add = [&] (int idx) {
        cnt[c[idx]]++;
    };
    auto del = [&] (int idx) {
        cnt[c[idx]]--;
    };
    function<void(int, int, bool)> dfs2 = [&] (int cur, int par, bool ck) {
        for (auto &e: v[cur]) if (par != e && hv[cur] != e) dfs2(e, cur, 1);
        if (hv[cur]) dfs2(hv[cur], cur, 0); add(cur);
        for (auto &e: v[cur]) if (par != e && hv[cur] != e) for (int i = tin[e]; i <= tout[e]; i++) add(pos[i]);
        col[cur] = cnt[c[cur]];
        if (ck) for (int i = tin[cur]; i <= tout[cur]; i++) del(pos[i]);
    };
    dfs(1, 0);
    dfs2(1, 0, 0);
    int ans = 1e9;
    vector<int> indeg(k + 5), outdeg(k + 5);
    function<void(int, int)> dfs3 = [&] (int cur, int par) {
        if (par && c[cur] != c[par]) {
            // cerr << cur << ' ' << ca[c[cur]] << ' ' << col[cur] << '\n';
            if (ca[c[cur]] - col[cur]) v2[c[cur]].emplace_back(c[par]), indeg[c[par]]++, outdeg[c[cur]]++, rev[c[par]].emplace_back(c[cur]);
        }
        for (auto &e: v[cur]) {
            if (par == e) continue;
            dfs3(e, cur);
        }
    };
    dfs3(1, 0);
    queue<int> q;
    for (int i = 1; i <= k; i++) if (!indeg[i]) q.emplace(i);
    while (!q.empty()) {
        int cur = q.front(); q.pop();
        for (auto &e: v2[cur]) if (!(--indeg[e])) q.emplace(e);
    }
    stack<int> cst;
    int csz = 0;
    vector<bool> f(k + 5), f2(k + 5);
    function<void(int, int)> dfs4 = [&] (int cur, int par) {
        if (f[cur]) return; f[cur] = 1;
        for (auto &e: v2[cur]) {
            if (par == e) continue;
            dfs4(e, cur);
        }
        cst.emplace(cur);
    };
    function<void(int, int)> dfs5 = [&] (int cur, int par) {
        if (f2[cur]) return; f2[cur] = 1; csz++;
        for (auto &e: rev[cur]) {
            if (par == e) continue;
            dfs5(e, cur);
        }
    };
    for (int i = 1; i <= k; i++) if (!outdeg[i]) ans = 0;
    for (int i = 1; i <= k; i++) if (!indeg[i]) f[i] = f2[i] = 1;
    for (int i = 1; i <= k; i++) if (!f[i]) dfs4(i, 0);
    while (!cst.empty()) {
        int cur = cst.top(); cst.pop();
        if (f2[cur]) continue; csz = 0;
        dfs5(cur, 0);
        ans = min(ans, csz - 1);
    }
    printf("%d", ans);
}

Compilation message (stderr)

capital_city.cpp: In lambda function:
capital_city.cpp:33:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   33 |         if (hv[cur]) dfs2(hv[cur], cur, 0); add(cur);
      |         ^~
capital_city.cpp:33:45: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   33 |         if (hv[cur]) dfs2(hv[cur], cur, 0); add(cur);
      |                                             ^~~
capital_city.cpp: In lambda function:
capital_city.cpp:63:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   63 |         if (f[cur]) return; f[cur] = 1;
      |         ^~
capital_city.cpp:63:29: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   63 |         if (f[cur]) return; f[cur] = 1;
      |                             ^
capital_city.cpp: In lambda function:
capital_city.cpp:71:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   71 |         if (f2[cur]) return; f2[cur] = 1; csz++;
      |         ^~
capital_city.cpp:71:30: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   71 |         if (f2[cur]) return; f2[cur] = 1; csz++;
      |                              ^~
capital_city.cpp: In function 'int main()':
capital_city.cpp:82:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   82 |         if (f2[cur]) continue; csz = 0;
      |         ^~
capital_city.cpp:82:32: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   82 |         if (f2[cur]) continue; csz = 0;
      |                                ^~~
capital_city.cpp:8:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 |     scanf("%d %d", &n, &k);
      |     ~~~~~^~~~~~~~~~~~~~~~~
capital_city.cpp:11:38: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 |     for (int i = 1; i < n; i++) scanf("%d %d", &x, &y), v[x].emplace_back(y), v[y].emplace_back(x);
      |                                 ~~~~~^~~~~~~~~~~~~~~~~
capital_city.cpp:12:39: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   12 |     for (int i = 1; i <= n; i++) scanf("%d", &c[i]), ca[c[i]]++;
      |                                  ~~~~~^~~~~~~~~~~~~

• Subtask 1: 1 / 1
• Subtask 2: 10 / 10
• Subtask 3: 30 / 30
• Subtask 4: 59 / 59