제출 #700935

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
700935		sunwukong123	Capital City (JOI20_capital_city)	C++14	100 / 100	359 ms	94900 KiB

capital_city

#include <bits/stdc++.h>
using namespace std;
#define int long long 
#define FOR(i,s,e) for(int i = s; i <= (int)e; ++i)
#define DEC(i,s,e) for(int i = s; i >= (int)e; --i)
#define IAMSPEED ios_base::sync_with_stdio(false); cin.tie(0);
#ifdef LOCAL
#define db(x) cerr << #x << "=" << x << "\n"
#define db2(x, y) cerr << #x << "=" << x << " , " << #y << "=" << y << "\n"
#define db3(a,b,c) cerr<<#a<<"="<<a<<","<<#b<<"="<<b<<","<<#c<<"="<<c<<"\n"
#define dbv(v) cerr << #v << ":"; for (auto ite : v) cerr << ite << ' '; cerr <<"\n"
#define dbvp(v) cerr << #v << ":"; for (auto ite : v) cerr << "{"  << ite.f << ',' << ite.s << "} "; cerr << "\n"
#define dba(a,ss,ee) cerr << #a << ":"; FOR(ite,ss,ee) cerr << a[ite] << ' '; cerr << "\n"
#define reach cerr << "LINE: " << __LINE__ << "\n";
#else
#define reach 
#define db(x)
#define db2(x,y)
#define db3(a,b,c)
#define dbv(v)
#define dbvp(v)
#define dba(a,ss,ee)
#endif
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define pb push_back
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define f first 
#define s second
#define g0(x) get<0>(x)
#define g1(x) get<1>(x)
#define g2(x) get<2>(x)
#define g3(x) get<3>(x)
typedef pair <int, int> pi;
typedef tuple<int,int,int> ti3;
typedef tuple<int,int,int,int> ti4;
int rand(int a, int b) { return a + rng() % (b-a+1); }
const int MOD = 1e9 + 7;
const int inf = (int)1e9 + 500;
const long long oo = (long long)1e18 + 500;
template <typename T> void chmax(T& a, const T b) { a=max(a,b); }
template <typename T> void chmin(T& a, const T b) { a=min(a,b); }
const int MAXN = 200005;
int n,k;
vector<int> adj[MAXN];
int C[MAXN];
vector<int> V[MAXN];
using namespace std;
int twok[MAXN][20];
int depth[MAXN];
int st[MAXN], en[MAXN], back[MAXN];
const int LOGN=18;
int ctr = 1;
void dfs(int x, int p, int d){
    st[x] = ctr++;
    back[st[x]] = x;
    depth[x] = d;
    twok[x][0] = p;
    for (int i = 1; i <= LOGN; i++){
        if (twok[x][i-1] == -1) break;
        twok[x][i] = twok[twok[x][i - 1]][i - 1]; // eg 16th parent = 8th parent 8th parent
    }
    for (int i = 0; i < adj[x].size(); i++){
        if (adj[x][i] != p) dfs(adj[x][i], x, d + 1);
    }
    en[x] = ++ctr; // changed
    back[en[x]] = x;
}
int kth_parent(int x, int k){
    for (int i = 0; i <= LOGN; i++){
        if (k & (1 << i)) x = twok[x][i];
        if (x <= -1) return -1;
    }
    return x;
}
int lca(int x, int y){
    if (depth[x] > depth[y]) {
        int dd = depth[x] - depth[y];
        x = kth_parent(x, dd);
    } else {
        int dd = depth[y] - depth[x];
        y = kth_parent(y, dd);
    }
    if (x == y) return x;
    
    for (int i = 17; i >= 0; i--){
        if (twok[x][i] != twok[y][i]){
            x = twok[x][i];
            y = twok[y][i];
        }
    }
    return twok[x][0];
}
int LCA[MAXN];
namespace tarjan {
	int num[MAXN], low[MAXN], weight[MAXN], whichScc[MAXN];
	bool instack[MAXN];
	vector<int> adjlist[MAXN];
	vector<int> sccadjlist[MAXN];
	stack<int> nodes;
	int ctr = 0;
	int sccptr = 0;
	void dfs(int x){
	    low[x] = num[x] = ctr++;
	    nodes.push(x);
	    instack[x] = true;
	    for (auto i : adjlist[x]){
	        if (num[i] == -1) dfs(i);
	        if (instack[i]) low[x] = min(low[i], low[x]);
	    }
	    
	    if (low[x] == num[x]){
	        // loop through the nodes of the found SCC.
	        while (instack[x]){
	            int v = nodes.top(); nodes.pop();
	            instack[v] = false;
	            whichScc[v] = sccptr;
	            weight[sccptr]++;
	        }
	        sccptr++;
	    }
	}
}
int32_t main() 
{
	IAMSPEED
	cin >> n >> k;
	FOR(i,1,n-1) {
		int a,b; cin >> a >> b;
		adj[a].pb(b);
		adj[b].pb(a);
	}
	FOR(i,1,n) cin >> C[i];
	FOR(i,1,n) {
		V[C[i]].pb(i);
	}
	memset(twok,-1,sizeof twok);
	dfs(1,-1,0);
	FOR(i,1,k) {
		sort(all(V[i]),[](int x, int y) {
			return st[x]<st[y];
		});
	}
	FOR(i,1,k) {
		LCA[i]=lca(V[i][0],V[i].back());
	}
	FOR(i,1,n) {
		if(i == LCA[C[i]]){

		} else {
			if(twok[i][0] != -1) {
				if(C[i] != C[twok[i][0]])tarjan::adjlist[C[i]].pb(C[twok[i][0]]);
			}
		}
	}
	memset(tarjan::num,-1,sizeof tarjan::num);
	FOR(i,1,k) {
		if(tarjan::num[i] == -1) tarjan::dfs(i);
	}
	FOR(i,1,k) {
		for(auto j:tarjan::adjlist[i]) {
			if(tarjan::whichScc[i] != tarjan::whichScc[j]) {
				tarjan::sccadjlist[tarjan::whichScc[i]].pb(tarjan::whichScc[j]);
			}
		}
	}

	int ans = inf;
	FOR(i,0,tarjan::sccptr-1) {
		if(tarjan::sccadjlist[i].size() == 0){
			chmin(ans, tarjan::weight[i]);
		}
	}
	cout << --ans;

	return (0-0) ; 
}

컴파일 시 표준 에러 (stderr) 메시지

capital_city.cpp: In function 'void dfs(long long int, long long int, long long int)':
capital_city.cpp:63:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   63 |     for (int i = 0; i < adj[x].size(); i++){
      |                     ~~^~~~~~~~~~~~~~~

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