Submission #966981

#	Time	Username	Problem	Language	Result	Execution time	Memory
966981		blackslex	Capital City (JOI20_capital_city)	C++17	1 / 100	3063 ms	128608 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);
    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]), st[c[i]] = i;
    vector<bool> cnt(k + 5);
    function<bool(int, int, int)> dfs = [&] (int cur, int par, int col) {
        bool add = (c[cur] == col);
        for (auto &e: v[cur]) {
            if (par == e) continue;
            add |= dfs(e, cur, col);
        }
        if (add) cnt[c[cur]] = 1;
        return add;
    };
    int ans = 1e9;
    vector<int> deg(k + 5);
    for (int i = 1; i <= k; i++) {
        cnt.assign(k + 5, 0);
        dfs(st[i], 0, i);
        for (int j = 1; j <= k; j++) if (i != j && cnt[j]) v2[i].emplace_back(j), deg[j]++, rev[j].emplace_back(i);
    }
    queue<int> q;
    for (int i = 1; i <= k; i++) if (!deg[i]) q.emplace(i);
    while (!q.empty()) {
        int cur = q.front(); q.pop();
        for (auto &e: v2[cur]) if (!(--deg[e])) q.emplace(e);
    }
    stack<int> cst;
    int csz = 0;
    vector<bool> f(k + 5), f2(k + 5);
    function<void(int, int)> dfs2 = [&] (int cur, int par) {
        if (f[cur]) return; f[cur] = 1;
        for (auto &e: v2[cur]) {
            if (par == e) continue;
            dfs2(e, cur);
        }
        cst.emplace(cur);
    };
    function<void(int, int)> dfs3 = [&] (int cur, int par) {
        if (f2[cur]) return; f2[cur] = 1; csz++;
        for (auto &e: rev[cur]) {
            if (par == e) continue;
            dfs3(e, cur);
        }
    };
    for (int i = 1; i <= k; i++) if (!deg[i]) f[i] = f2[i] = 1;
    for (int i = 1; i <= k; i++) if (!f[i]) dfs2(i, 0);
    while (!cst.empty()) {
        int cur = cst.top(); cst.pop();
        if (f2[cur]) continue; csz = 0;
        dfs3(cur, 0);
        ans = min(ans, csz - 1);
    }
    printf("%d", ans == 1e9 ? 0 : ans);
}

Compilation message (stderr)

capital_city.cpp: In lambda function:
capital_city.cpp:40:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   40 |         if (f[cur]) return; f[cur] = 1;
      |         ^~
capital_city.cpp:40:29: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   40 |         if (f[cur]) return; f[cur] = 1;
      |                             ^
capital_city.cpp: In lambda function:
capital_city.cpp:48:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   48 |         if (f2[cur]) return; f2[cur] = 1; csz++;
      |         ^~
capital_city.cpp:48:30: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   48 |         if (f2[cur]) return; f2[cur] = 1; csz++;
      |                              ^~
capital_city.cpp: In function 'int main()':
capital_city.cpp:58:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   58 |         if (f2[cur]) continue; csz = 0;
      |         ^~
capital_city.cpp:58:32: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   58 |         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]), st[c[i]] = i;
      |                                  ~~~~~^~~~~~~~~~~~~

• Subtask 1: 1 / 1
• Subtask 2: 0 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 59