hdu 2988 Dark roads

原题链接：http://acm.hdu.edu.cn/showproblem.php?pid=2988
最小生成树。。

#include<algorithm>#include<iostream>#include<cstdlib>#include<cstring>#include<cstdio>#include<vector>#include<queue>#include<set>using std::set;using std::sort;using std::pair;using std::swap;using std::multiset;using std::priority_queue;#define pb(e) push_back(e)#define sz(c) (int)(c).size()#define mp(a, b) make_pair(a, b)#define all(c) (c).begin(), (c).end()#define iter(c) decltype((c).begin())#define cls(arr, val) memset(arr, val, sizeof(arr))#define cpresent(c, e) (find(all(c), (e)) != (c).end())#define rep(i, n) for(int i = 0; i < (int)n; i++)#define tr(c, i) for(iter(c) i = (c).begin(); i != (c).end(); ++i)const int N = 200010;const int INF = 0x3f3f3f3f;typedef unsigned long long ull;struct edge {    int u, v, w;    inline bool operator<(const edge &x) const {        return w < x.w;    }}G[N];struct Kruskal {    int E, sum, par[N], rank[N];    inline void init(int n) {        E = sum = 0;        rep(i, n + 1) {            par[i] = i, rank[i] = 0;        }    }    inline void built(int m) {        int u, v, w;        while (m--) {            scanf("%d %d %d", &u, &v, &w);            G[E++] = { u, v, w }, sum += w;        }    }    inline int find(int x) {        while (x != par[x]) {            x = par[x] = par[par[x]];        }        return x;    }    inline bool unite(int x, int y) {        x = find(x), y = find(y);        if (x == y) return false;        if (rank[x] < rank[y]) {            par[x] = y;        } else {            par[y] = x;            rank[x] += rank[x] == rank[y];        }        return true;    }    inline int kruskal() {        int ans = 0;        sort(G, G + E);        rep(i, E) {            edge &e = G[i];            if (unite(e.u, e.v)) {                ans += e.w;            }        }        return ans;    }    inline void solve(int n, int m) {        init(n), built(m);        printf("%d\n", sum - kruskal());    }}go;int main() {#ifdef LOCAL    freopen("in.txt", "r", stdin);    freopen("out.txt", "w+", stdout);#endif    int n, m;    while (~scanf("%d %d", &n, &m), n + m) {        go.solve(n, m);    }    return 0;}