CF #756 div3

#include 
#include 
#include 
using namespace std;

int T;

int getEven(int x)
{
	int cnt = 0;
	int t = x;
	while (t) {
		t/= 10;
		cnt++;
	}	
	
	int pos = -1;
	t = x;
	int i = 1;
	while (t) {
		int b = t % 10;
		if (b % 2 == 0) pos = i;
		t /= 10, i++;
	}
	
	if (pos == -1) return -1;
	else return cnt - pos + 1;
}

int main()
{
	cin >> T;
	while (T--)
	{
		int x;
		cin >> x;
		if (x % 2 == 0) cout << 0 << 'n';
		else {
			int pos = getEven(x);
			if (pos == 1) cout << 1 << 'n';
			else if (pos == -1) cout << -1 << 'n';
			else cout << 2 << 'n';
		}
	}
	return 0;
} 

#include 
#include 
#include 
using namespace std;

int T;
int a, b;

bool check(int x)
{
	if (x > a || x > b) return false;
	int sum = a + b - 2*x;
	return sum / 2 >= x;	
}

int main()
{
	cin >> T;
	while (T--){
		cin >> a >> b;
		int r = min((a+b)/4, min(a, b));
		int l = 1;
		if (a == 0 || b == 0 || l > r) cout << 0 << 'n';
		else {
			while (l < r) {
				int mid = (l + r + 1) >> 1;
				if (check(mid)) l = mid;
				else r = mid - 1;
			}
			cout << l << 'n';
		} 
	}
	return 0;
} 

#include 
#include 
#include 
using namespace std;

const int N = 200010;

int T;
int n;
int fa[N], w[N], dep[N];

bool check()
{
	for (int i=1; i<=n; i++) 
	{
	//	cout << " i, fa[i], dep[i], dep[fa[i]] : " << i << ' ' << fa[i] << ' ' << dep[i];
	//	cout << ' ' << dep[fa[i]] << endl;
		if (dep[fa[i]] > dep[i]) return true;
	}
	return false;
}

int main()
{
	cin >> T;
	while (T--)
	{
		memset(fa, 0, sizeof fa);
		scanf("%d", &n);
		for (int i=1; i<=n; i++)
			scanf("%d", &fa[i]);
		for (int i=1; i<=n; i++)
		{
			int x;
			scanf("%d", &x);
			dep[x] = i;
		}
		
		if (check()) {
			cout << -1 << 'n';
			continue;
		}
		for (int i=1; i<=n; i++) {
			if (fa[i] == i) cout << 0 << ' ';
			else cout << 10 * (dep[i] - dep[fa[i]]) << ' ';
		}
	}
	return 0;
}

#include 
#include 
#include 
#include 
using namespace std;

const int N = 200010, M = 400010;

typedef pair PII;

int T;
int n, k;
int a[N], v[M], nex[M], tot;
int f[N];	// 每个点最早出现朋友的时刻
int dep[N]; 
int d[N];

void addEdge(int fr, int to) {
	v[++tot] = to, nex[tot] = a[fr], a[fr] = tot;
}

int dfs(int u, int fa)
{
	dep[u] = dep[fa] + 1;

	if (f[u] == 0) return f[u] + 1;
	
	for (int i=a[u]; i; i=nex[i]) {
		int to = v[i];
		if (to == fa) continue;
		
		int temp = dfs(to, u);
		f[u] = min(f[u], temp);
	}

	return f[u] + 1; 
} 

bool find(int u, int fa)
{
	//cout << "u, dep[u]:" << u << ' ' << dep[u] << endl; 
	if (d[u] == 1 && dep[u] > 0) return true;
	
	for (int i=a[u]; i; i=nex[i]) {
		int to = v[i];
		if (f[to] <= dep[to] || to == fa) continue;
		if (find(to, u)) return true;
	}
	return false;	
}

int main()
{
	scanf("%d", &T);
	while (T--)
	{
		scanf("%d%d", &n, &k);
		memset(f, 0x3f, sizeof f);
		memset(a, 0, sizeof a);
		memset(d, 0, sizeof d);
		memset(dep, 0, sizeof dep);
		
		for (int i=1; i<=k; i++) {
			int x;
			scanf("%d", &x);
			f[x] = 0;
		}
		
		for (int i=1; i 
E-2 
#include 
#include 
#include 
#include 
using namespace std;

const int N = 200010, M = 400010;

typedef pair PII;

int T;
int n, k;
int a[N], v[M], nex[M], tot;
int f[N];	// 每个点最早出现朋友的时刻
int dep[N]; 
int d[N];
int fri;	// 最少的朋友数量 

void addEdge(int fr, int to) {
	v[++tot] = to, nex[tot] = a[fr], a[fr] = tot;
}

int dfs(int u, int fa)
{
	dep[u] = dep[fa] + 1;

	if (f[u] == 0) return f[u] + 1;
	
	for (int i=a[u]; i; i=nex[i]) {
		int to = v[i];
		if (to == fa) continue;
		
		int temp = dfs(to, u);
		f[u] = min(f[u], temp);
	}

	return f[u] + 1; 
} 

bool find(int u, int fa)
{
	if (d[u] == 1 && dep[u] > 0) return true;
	
	for (int i=a[u]; i; i=nex[i]) {
		int to = v[i];
		if (f[to] <= dep[to]) {
			fri++;
			continue;
		} 
		if (to == fa) continue;
		if (find(to, u)) return true;
	}
	return false;	
}

int main()
{
	scanf("%d", &T);
	while (T--)
	{
		scanf("%d%d", &n, &k);
		memset(f, 0x3f, sizeof f);
		memset(a, 0, sizeof a);
		memset(d, 0, sizeof d);
		memset(dep, 0, sizeof dep);
		
		for (int i=1; i<=k; i++) {
			int x;
			scanf("%d", &x);
			f[x] = 0;
		}
		
		for (int i=1; i 
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