Submission #2167584


Source Code Expand

#include <iostream>
#include <vector>
#include <utility>
#define inf 1000000000

using namespace std;

struct edge{
	int to, cap, rev;
	edge(int a, int b, int c){
		to = a, cap = b, rev = c;
	}
};

int N;
vector<int> tree[100005];
int depth[100005];
vector<edge> G[205];
int S, T;
bool used[205];

void dfs2(int v, int prev, int dep)
{
	depth[v] = dep;
	for(int i = 0; i < tree[v].size(); i++){
		if(tree[v][i] != prev) dfs2(tree[v][i], v, dep+1);
	}
}

int dfs(int v, int f)
{
	used[v] = true;
	if(v == T) return f;
	
	int ret;
	for(int i = 0; i < G[v].size(); i++){
		if(used[G[v][i].to] || G[v][i].cap <= 0) continue;
		ret = dfs(G[v][i].to, min(f, G[v][i].cap));
		if(ret > 0){
			G[v][i].cap -= ret;
			G[G[v][i].to][G[v][i].rev].cap += ret;
			return ret;
		}
	}
	return 0;
}

void add_edge(int s, int t, int cap)
{
	G[s].push_back(edge(t, cap, G[t].size()));
	G[t].push_back(edge(s, 0, G[s].size()-1));
}

int main(void)
{
	cin >> N;
	int a, b;
	for(int i = 0; i < N-1; i++){
		cin >> a >> b;
		tree[a].push_back(b);
		tree[b].push_back(a);
	}
	S = N+1, T = N+2;
	
	dfs2(1, -1, 0);
	for(int i = 1; i <= N; i++){
		if(depth[i] % 2){
			add_edge(S, i, 1);
			for(int j = 0; j < tree[i].size(); j++) add_edge(i, tree[i][j], 1);
		}
		else add_edge(i, T, 1);
	}
	
	int ans = 0, flow;
	while(1){
		for(int i = 1; i <= T; i++) used[i] = false;
		flow = dfs(S, inf);
		if(flow <= 0) break;
		ans += flow;
	}
	
	if(N % 2 == 0 && ans == N/2) cout << "Second" << endl;
	else cout << "First" << endl;
	return 0;
}

Submission Info

Submission Time
Task D - Black and White Tree
User leaf1415
Language C++14 (GCC 5.4.1)
Score 0
Code Size 1593 Byte
Status RE
Exec Time 207 ms
Memory 6272 KB

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 0 / 900
Status
AC × 3
AC × 7
RE × 32
Set Name Test Cases
Sample sample1.txt, sample2.txt, sample3.txt
All sample1.txt, sample2.txt, sample3.txt, in1.txt, in10.txt, in11.txt, in12.txt, in13.txt, in14.txt, in15.txt, in16.txt, in17.txt, in18.txt, in19.txt, in2.txt, in20.txt, in21.txt, in22.txt, in23.txt, in24.txt, in25.txt, in26.txt, in27.txt, in28.txt, in29.txt, in3.txt, in30.txt, in31.txt, in32.txt, in33.txt, in4.txt, in5.txt, in6.txt, in7.txt, in8.txt, in9.txt, sample1.txt, sample2.txt, sample3.txt
Case Name Status Exec Time Memory
in1.txt RE 187 ms 6272 KB
in10.txt RE 186 ms 6272 KB
in11.txt RE 187 ms 6144 KB
in12.txt RE 106 ms 2944 KB
in13.txt RE 186 ms 6144 KB
in14.txt RE 189 ms 6144 KB
in15.txt RE 187 ms 6144 KB
in16.txt RE 186 ms 6144 KB
in17.txt RE 187 ms 6144 KB
in18.txt RE 188 ms 6144 KB
in19.txt RE 185 ms 6144 KB
in2.txt RE 188 ms 6272 KB
in20.txt RE 187 ms 6144 KB
in21.txt RE 188 ms 6272 KB
in22.txt RE 187 ms 6272 KB
in23.txt RE 190 ms 6144 KB
in24.txt RE 186 ms 6144 KB
in25.txt RE 188 ms 6144 KB
in26.txt RE 187 ms 6144 KB
in27.txt RE 190 ms 6144 KB
in28.txt AC 2 ms 2560 KB
in29.txt RE 188 ms 6144 KB
in3.txt RE 187 ms 6272 KB
in30.txt RE 186 ms 6144 KB
in31.txt RE 188 ms 6144 KB
in32.txt RE 186 ms 6144 KB
in33.txt RE 207 ms 6144 KB
in4.txt RE 196 ms 6272 KB
in5.txt RE 194 ms 6272 KB
in6.txt RE 191 ms 6272 KB
in7.txt RE 204 ms 6272 KB
in8.txt RE 201 ms 6272 KB
in9.txt RE 190 ms 6272 KB
sample1.txt AC 2 ms 2560 KB
sample2.txt AC 2 ms 2560 KB
sample3.txt AC 2 ms 2560 KB