UVa 10600 ACM contest and Blackout（ 次小生成树）

很裸的模板题

求最小生成树，和次小生成树

代码：

#include <cstdio>#include <cstring>#include <algorithm>using namespace std;const int N = 110;const int M = 310;const int INF = 100000000;int n, m, map[N][N], p[N], d[N], f[N][N], s1, s2, mark[N];void prim() {    for ( int i = 1; i <= n; ++i ) p[i] = -1, d[i] = INF;    int mi, v;    bool vis[N];    memset(vis, 0, sizeof(vis));    d[1] = 0, s1 = 0;    for ( int u = 0; u < n; ++u ) {        mi = INF;        for ( int i = 1; i <= n; ++i ) if ( !vis[i] && mi > d[i] ) mi = d[i], v = i;        s1 += mi;        vis[v] = true;        for ( int i = 1; i <= n; ++i ) if ( !vis[i] && d[i] > map[v][i] ) d[i] = map[v][i], p[i] = v;    }}void dfs( int v ) {    for ( int u = 1; u <= n; ++u ) {        if ( !mark[u] && p[u] == v && u != v ) {            mark[u] = true;            for ( int x = 1; x <= n; ++x ) if ( mark[x] && u != x ) {               f[x][u] = f[u][x] = max( f[x][v], map[u][v] );             }            dfs(u);        }    }}int main() {    int T;    scanf("%d", &T);    while ( T-- ) {        scanf("%d%d", &n, &m);        for ( int i = 1; i <= n; ++i )             for ( int j = 1; j <= n; ++j ) map[i][j] = INF;        while ( m-- ) {            int a, b, c;            scanf("%d%d%d", &a, &b, &c);            map[a][b] = map[b][a] = c;        }        prim();        memset( f, 0, sizeof(f));        memset( mark, 0, sizeof(mark));        mark[1] = true;        dfs( 1 );        s2 = INF;        /*for ( int i = 1; i <= n; ++i ) {            for ( int j = 1; j <= n; ++j )                 printf("%d ", f[i][j] );            printf("\n");        }*/        for ( int i = 1; i <= n; ++i )             for ( int j = i+1; j <= n; ++j ) {                if ( j != p[i] && i != p[j] ) {                    s2 = ( s2 <= s1 - f[i][j] + map[i][j] ? s2 : s1 - f[i][j] + map[i][j] );                 }            }        printf("%d %d\n", s1, s2);    }}