Submission #863421

#	Time	Username	Problem	Language	Result	Execution time	Memory
863421		maks007	Paths (BOI18_paths)	C++14	43 / 100	3082 ms	25336 KiB

paths

// Bismi Allah
#include "bits/stdc++.h"

using namespace std;

#define int long long

void do_another(int n, int m, int k, int ans) {
	int changes = 1;
	vector <int> color(n), g[n], used(n), permutation(k);
	set <int> colorUsed;
	function <void(int, int)> dfs=[&](int v, int cur) {
		if(cur >= changes) {
			ans++;
		}
		if(cur == permutation.size() - 1) return;
		used[v] = 1;
		for(auto u : g[v] ) {
			if(!used[u] && color[u] == permutation[cur+1]) dfs(u, cur + 1);
		}
		used[v]=0;
	};
	
	for(int i = 0; i < n; i ++) cin >> color[i];
	for(int i = 0; i < m; i ++) {
		int u, v;
		cin >> u >> v;
		u --, v --;
		g[u].push_back(v);
		g[v].push_back(u);
	}
	vector <int> prev;	
	for(int i = 0; i < k; i ++) permutation[i] = i + 1;
	do{
		if(prev.size() > 0) {
			for(int i = 0; i < permutation.size(); i ++) {
				if(prev[i] != permutation[i]) {
					changes = i;
					break;
				}
			}
			changes = max(changes, 1LL);
		}
		for(int i = 0; i < n; i ++) {
			if(color[i] == permutation[0]) dfs(i, 0);
		}
		prev = permutation;
	} while(next_permutation(permutation.begin(), permutation.end()));		
	
	cout << ans;
	exit(0);
}

signed main () {
	ios::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	int n, m, k, ans = 0;
	cin >> n >> m >> k;
	if(k > 3) {
		do_another(n, m, k, ans);
		return 0;
	}
	vector <int> color(n), g[n];
	for(int i = 0; i < n; i ++) cin >> color[i];
	for(int i = 0; i < m; i ++) {
		int u, v;
		cin >> u >> v;
		u --, v --;
		g[u].push_back(v);
		g[v].push_back(u);
	}
	for(int i = 0; i < n; i ++) {
		for(auto u : g[i]) {
			if(color[i] != color[u]) ans ++;
		}
		int color1 = 0, color2 = 0, forOne = -1;
		for(auto u : g[i]) {
			if(color[u] == color[i]) continue;
			if(forOne == -1) {
				forOne = color[u];
				color1 ++;
			}else {
				if(forOne == color[u]) color1 ++;
				else color2 ++;
			}
		}
		ans += 2 * color1 * color2;
	}
	cout << ans;
	return 0;
}

Compilation message (stderr)

paths.cpp: In lambda function:
paths.cpp:16:10: 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]
   16 |   if(cur == permutation.size() - 1) return;
      |      ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
paths.cpp: In function 'void do_another(long long int, long long int, long long int, long long int)':
paths.cpp:36:21: 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]
   36 |    for(int i = 0; i < permutation.size(); i ++) {
      |                   ~~^~~~~~~~~~~~~~~~~~~~

• Subtask 1: 23 / 23
• Subtask 2: 20 / 20
• Subtask 3: 0 / 27
• Subtask 4: 0 / 30