UVa11631 Dark Roads（最小生成树，邻接表）

很裸的一道求最小生成树的题，只是数据很大，要用邻接表来存储

代码：

#include <cstdio>
#include <cstring>
#include <vector>
using namespace std;

const int N = 200010;
const long long INF = 10000000000;
int n, m, id, head
;
long long sum;
struct edge{
int t, next;
int l;
}e[N*2];
long long prim() {
int u = n - 1, v;
long long mi, ans = 0, d
;
bool vis
;
for ( int i = 0; i < n; ++i ) d[i] = INF;
memset(vis, 0, sizeof(vis));
d[0] = 0;

for ( int t = 0; t <= u; ++t ) {
mi = INF;
for ( int i = 0; i < n; ++i ) if ( !vis[i] && d[i] < mi ) {
v = i, mi = d[i];
}
//printf("%d %lld\n", v, mi);
if ( mi == INF ) break;
ans += mi;
vis[v] = true;
for ( int i = head[v]; i != -1; i = e[i].next ) {
int x = e[i].t, c = e[i].l;
if ( !vis[x] && d[x] > c ) d[x] = c;
}
}
return ans;
}
void add( int u, int v, int c ) {
e[id].next = head[u], e[id].t = v, e[id].l = c, head[u] = id++;
e[id].next = head[v], e[id].t = u, e[id].l = c, head[v] = id++;
}

int main()
{
while ( scanf("%d%d", &n, &m) != EOF && !( m == 0 && n == 0 ) ) {
sum = 0, id = 0;
for ( int i = 0; i <= n; ++i ) head[i] = -1;
while ( m-- ) {
int s, t, l;
scanf("%d%d%d", &s, &t, &l);
sum += l;
add( s, t, l );
}
printf("%lld\n", sum - prim());
}
}