企业还做网站吗,桂林两江四湖景区,淘宝网官网,网络营销推广的方式都有哪些P2495 [SDOI2011]消耗战 代码 有的虚树建立好像把一些点没建#xff0c;他们不用判断是否是关键点#xff1b; il void push(int x) {if(t 1) {s[ t] x;return;}int l lca(x, s[t]); if(l s[t]) return; //这句话我没看懂#xff0c;因该就是这#xff0c;脑子好乱他们不用判断是否是关键点 il void push(int x) {if(t 1) {s[ t] x;return;}int l lca(x, s[t]); if(l s[t]) return; //这句话我没看懂因该就是这脑子好乱while(t 1 dfn[s[t - 1]] dfn[l]) v[s[t - 1]].push_back(s[t]), --t;if(s[t] ! l) v[l].push_back(s[t]), s[t] l;s[ t] x; } 摘自 洛谷 Nemlit P2495 [SDOI2011]消耗战 题解这建虚树好精简 #include iostream #include algorithm #include cstring #include vector #include deque #include stack #define mid (lr1) #define lowbit(x) (x-x) using namespace std; typedef long long LL; typedef pairint,int PII; const int N 2.5e5 4;int h[N], ne[N1], e[N1], w[N1], idx; void add(int a, int b, int c){e[idx]b,ne[idx]h[a],w[idx]c,h[a]idx;return ;}int dfn[N], cv, fa[N][20], deep[N]; LL mi[N]; void dfs(int u, int f) {dfn[u] cv; deep[u] deep[f]1;for(int i 1;i 20;i ) fa[u][i] fa[fa[u][i-1]][i-1];for(int i h[u];~i ;i ne[i]){if(e[i] f)continue;fa[e[i]][0] u; mi[e[i]] min(mi[u], (LL)w[i]);dfs(e[i], u);} } int lca(int u, int v) {if(deep[u]deep[v])swap(u, v);int x deep[u] - deep[v];for(int i 0;i 20;i )if(xi1)u fa[u][i];if(u v)return v;for(int i 19;i 0;i --)if(fa[u][i] ! fa[v][i])u fa[u][i], v fa[v][i];return fa[u][0]; }int a[N]; bool dis[N]; bool cmp(int a,int b){return dfn[a]dfn[b];}LL dfs(int u) {if(h[u] -1)return mi[u]; LL ans 0;for(int i h[u]; ~i;i ne[i])if(dis[e[i]])ans mi[e[i]], dfs(e[i]);else ans dfs(e[i]);h[u] -1;return min(mi[u], ans); } stackint st; LL build(int n) {st.push(1); idx 0;int tmp;for(int i 1;i n;i ){int lc lca(a[i], st.top());while(lc ! st.top()){tmp st.top(); st.pop();if(dfn[st.top()] dfn[lc])st.push(lc);add(st.top(), tmp, 0);}st.push(a[i]);dis[a[i]] 1;}while(st.size() 1){tmp st.top(); st.pop();add(st.top(), tmp, 0);}st.pop();return dfs(1); } int main() {int n, m;scanf(%d, n);for(int i 1;i n;i ) h[i] -1;memset(mi, 0x7f, sizeof mi);for(int i 1;i n;i ){int a, b, c;scanf(%d%d%d, a, b, c);add(a, b, c);add(b, a, c);}dfs(1, 0);for(int i 1;i n;i )h[i] -1;scanf(%d, m);while(m--){int k;scanf(%d, k);for(int i 1;i k;i ) scanf(%d, ai);sort(a1, ak1, cmp);printf(%lld\n, build(k));for(int i 1;i k;i ) dis[a[i]] 0;} return 0; }