Submission #393115

#	Time	Username	Problem	Language	Result	Execution time	Memory
393115		patrikpavic2	Hard route (IZhO17_road)	C++17	100 / 100	1066 ms	115584 KiB

road

#include <cstdio>
#include <vector>
#include <algorithm>
#include <cstring>

#define X first
#define Y second
#define PB push_back

using namespace std;

typedef long long ll;
typedef pair < int , int > pii;
typedef pair < ll , ll > pll;

const int N = 1e6 + 500;

int n;
vector < int > v[N];
pll dis[N], gor[N];
int dep[N];
ll cnt[N][3];

inline pll add(const pll &A, const pll &B){
	return {(A.X > B.X ? A.X : B.X), A.Y * (A.X >= B.X) + B.Y * (B.X >= A.X)};
}

pll dolje(int x, int lst){
	dep[x] = dep[lst] + 1;
	dis[x] = {0, 1};
	for(int y : v[x]){
		if(y == lst) continue;
		pll nxt = dolje(y, x);
		nxt.X++; dis[x] = add(dis[x], nxt);
	}
	pll cur = {1, 1};
	for(int y : v[x]){
		if(y == lst) continue;
		gor[y] = add(gor[y], cur);
		pll tmp = dis[y]; tmp.X += 2;
		cur = add(cur, tmp);
	}
	reverse(v[x].begin(), v[x].end());
	cur = {0, 0};
	for(int y : v[x]){
		if(y == lst) continue;	
		gor[y] = add(gor[y], cur);
		pll tmp = dis[y]; tmp.X += 2;
		cur = add(cur, tmp);
	}
	reverse(v[x].begin(), v[x].end());
	return dis[x];
}

void gore(int x, int lst){
	for(int y : v[x]){
		if(y == lst) continue;
		gor[y] = add(gor[y], {gor[x].X + 1, gor[x].Y});
		gore(y, x);
	}
}

pll calc_dis(int x, int y){
	if(dep[x] > dep[y])
		return {dis[x].X + 1, dis[x].Y};
	return {gor[y].X, gor[y].Y};
}

ll ch(int n, int k){
	int ret = 1;
	for(int i = 0;i < k;i++)
		ret *= (n - i), ret /= i + 1;
	return ret;
}

int main(){
	for(int i = 0;i < N;i++) dis[i].X = -1;
	scanf("%d", &n);
	for(int i = 1;i < n;i++){
		int x, y; scanf("%d%d", &x, &y);
		v[x].PB(y), v[y].PB(x);
	}
	dolje(1, 1); gore(1, 1);
	pll sol = {0, 0};
	for(int i = 1;i <= n;i++){
		vector < int > sus;
		
		for(int nxt : v[i]){
			pll nw = calc_dis(nxt, i);
			sus.PB(nw.X);
			cnt[nw.X][2] += nw.Y * cnt[nw.X][1];
			cnt[nw.X][1] += nw.Y;
		}
		for(int j = 0;j < 3;j++)
			for(int i = (int)sus.size() - 1; i ;i--)
				if(sus[i - 1] < sus[i]) swap(sus[i], sus[i - 1]);
		if((int)sus.size() > 2){
			if(sus[0] > sus[1] && sus[1] > sus[2])
				sol = add(sol, {(ll)(sus[1] + sus[2]) * sus[0], cnt[sus[1]][1] * cnt[sus[2]][1]});
			else if(sus[0] == sus[1] && sus[1] == sus[2])
				sol = add(sol, {(ll)(sus[1] + sus[2]) * sus[0], cnt[sus[0]][2]});
			else if(sus[0] > sus[1])
				sol = add(sol, {(ll)(sus[1] + sus[2]) * sus[0], cnt[sus[1]][2]});				
			else
				sol = add(sol, {(ll)(sus[1] + sus[2]) * sus[0], cnt[sus[1]][2] & cnt[sus[2]][1]});						
		}
		for(int x : sus){
			cnt[x][1] = 0, cnt[x][2] = 0;
		}
	}
	if(!sol.X) sol.Y++;
	printf("%lld %lld\n", sol.X, sol.Y);
	return 0;
}

Compilation message (stderr)

road.cpp: In function 'int main()':
road.cpp:78:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   78 |  scanf("%d", &n);
      |  ~~~~~^~~~~~~~~~
road.cpp:80:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   80 |   int x, y; scanf("%d%d", &x, &y);
      |             ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 19 / 19
• Subtask 2: 33 / 33
• Subtask 3: 48 / 48