You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
52 lines
1.3 KiB
C++
52 lines
1.3 KiB
C++
#define _CRT_SECURE_NO_WARNINGS
|
|
#define _SILENCE_CXX17_C_HEADER_DEPRECATION_WARNING
|
|
#include <bits/stdc++.h>
|
|
using namespace std;
|
|
template <int N>
|
|
struct DisJointSet
|
|
{
|
|
int f[N], rk[N];
|
|
int find(int x) { return f[x] == x ? x : f[x] = find(f[x]); }
|
|
void link(int x, int y)
|
|
{
|
|
if (rk[x] > rk[y]) swap(x, y);
|
|
f[x] = y, rk[y] = max(rk[y], rk[x] + 1);
|
|
}
|
|
void reset()
|
|
{
|
|
for (int i = 0; i < N; i++) f[i] = i;
|
|
memset(rk, 0, sizeof(rk));
|
|
}
|
|
};
|
|
struct edge
|
|
{
|
|
int f, t, l;
|
|
bool operator<(const edge &rhs) const { return l < rhs.l; }
|
|
};
|
|
edge E[105 * 105 / 2];
|
|
int main()
|
|
{
|
|
DisJointSet<105> U;
|
|
for (int n, m; scanf("%d%d", &n, &m), n | m;)
|
|
{
|
|
for (int i = 0; i < m; i++)
|
|
scanf("%d%d%d", &E[i].f, &E[i].t, &E[i].l);
|
|
sort(E, E + m);
|
|
unsigned ans = -1;
|
|
for (int i = 0; i < m; i++)
|
|
{
|
|
U.reset();
|
|
int cnt = 1;
|
|
unsigned tmp = -1;
|
|
for (int j = i; j < m && cnt < n; j++)
|
|
{
|
|
tmp = E[j].l - E[i].l;
|
|
int f1 = U.find(E[j].f), f2 = U.find(E[j].t);
|
|
if (f1 != f2) U.link(f1, f2), cnt++;
|
|
}
|
|
if (cnt == n) ans = min(ans, tmp);
|
|
}
|
|
printf("%d\n", ans);
|
|
}
|
|
return 0;
|
|
} |