Submission #660916

#	Time	Username	Problem	Language	Result	Execution time	Memory
660916		Trisanu_Das	Mag (COCI16_mag)	C++17	0 / 120	698 ms	262144 KiB

mag

#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e6 + 10;
vector<int> g[maxn], len[maxn];
int a[maxn];
int memo[maxn];
int n;
 
void add(int x, int t) {
	if (len[x][0] <= t) swap(len[x][0], t);
	len[x][1] = max(len[x][1], t);
}
 
int get(int x, int t=0) {
	return (a[x] == 1) * (len[x][t] + 1);
}
 
int dfs(int x, int p = 0) {
	len[x] = {0, 0};
	for (int v : g[x]) {
		if (v == p) continue;
		add(x, dfs(v, x));
	}
	return get(x);
}
 
int dfs_root(int x, int p = 0) {
	if (p) {
		int l = (a[p] == 1) *  get(p, len[p][0] == get(x));
		add(x, l);
	}
	memo[x] = len[x][0] + len[x][1];
	for (int v : g[x]) {
		if (v == p) continue;
		dfs_root(v, x);
	}
}
 
int main() {
	scanf("%d", &n);
	for (int i = 1; i <= n-1; ++i) {
		int a, b;
		scanf("%d %d", &a, &b);
		g[a].emplace_back(b);
		g[b].emplace_back(a);
	}
	for (int i = 1; i <= n; ++i) {
		scanf("%d", a+i);
	}
	dfs(1);
	dfs_root(1);
	int x = -1, y = -1;
	for (int i = 1; i <= n; ++i) {
		if (x == -1 or x *1ll* (memo[i] + 1) > a[i] *1ll* y) {
			x = a[i];
			y = memo[i] + 1;
		}
	}
	int g = __gcd(x, y);
	printf("%d/%d\n", x/g, y/g);
	return 0;
}

Compilation message (stderr)

mag.cpp: In function 'int dfs_root(int, int)':
mag.cpp:37:1: warning: no return statement in function returning non-void [-Wreturn-type]
   37 | }
      | ^
mag.cpp: In function 'int main()':
mag.cpp:40:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 |  scanf("%d", &n);
      |  ~~~~~^~~~~~~~~~
mag.cpp:43:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |   scanf("%d %d", &a, &b);
      |   ~~~~~^~~~~~~~~~~~~~~~~
mag.cpp:48:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   48 |   scanf("%d", a+i);
      |   ~~~~~^~~~~~~~~~~

• Subtask 1: 0 / 12
• Subtask 2: 0 / 12
• Subtask 3: 0 / 12
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• Subtask 10: 0 / 12