bzoj1572:贪心。先按时间顺序排序,然后用优先队列,如果时间不矛盾直接插入,否则判断队列中w最小的元素是否替换掉。(没用llWA了一次
#include<cstdio> #include<cstring> #include<iostream> #include<queue> #include<algorithm> using namespace std; #define REP(i,s,t) for(int i=s;i<=t;i++) #define dwn(i,s,t) for(int i=s;i>=t;i--) #define ll long long #define clr(x,c) memset(x,c,sizeof(x)) int read(){ int x=0;char c=getchar(); while(!isdigit(c)) c=getchar(); while(isdigit(c)) x=x*10+c-‘0‘,c=getchar(); return x; } const int nmax=100005; struct Node{ int num,w; bool operator<(const Node&rhs)const{ return num<rhs.num;} }; Node Nodes[nmax]; struct node{ int num,w; bool operator<(const node&rhs)const{ return w>rhs.w;} }; node nodes[nmax]; priority_queue<node>q; int main(){ int n=read(); REP(i,1,n) Nodes[i].num=read(),Nodes[i].w=read(); sort(Nodes+1,Nodes+n+1); REP(i,1,n) nodes[i].num=Nodes[i].num,nodes[i].w=Nodes[i].w; REP(i,1,n){ node o=nodes[i]; if(o.num>q.size()) { q.push(o);continue; } node tp=q.top(); if(tp.w<o.w) q.pop(),q.push(o); } ll ans=0; while(!q.empty()) ans+=q.top().w,q.pop(); printf("%lld\n",ans); return 0; }
bzoj1574:贪心,将不能到达的点与相连的点集删除,然后dfs。(两个数组名相同RE了一次
#include<cstdio> #include<cstring> #include<iostream> #include<algorithm> using namespace std; #define REP(i,s,t) for(int i=s;i<=t;i++) #define dwn(i,s,t) for(int i=s;i>=t;i--) #define clr(x,c) memset(x,c,sizeof(x)) #define qwq(x) for(edge *o=head[x];o;o=o->next) #define op() clr(head,0);pt=edges; int read(){ int x=0;char c=getchar(); while(!isdigit(c)) c=getchar(); while(isdigit(c)) x=x*10+c-‘0‘,c=getchar(); return x; } const int nmax=30005; const int maxn=200005; struct edge{ int to;edge *next; }; edge edges[maxn],*pt,*head[nmax]; bool vis[nmax],V[nmax]; void adde(int u,int v){ pt->to=v;pt->next=head[u];head[u]=pt++; pt->to=u;pt->next=head[v];head[v]=pt++; } void dfs(int x){ V[x]=true; qwq(x) if(vis[o->to]&&!V[o->to]) dfs(o->to); } int main(){ op();clr(vis,true);clr(V,false); int N=read(),M=read(),P=read(),u,v; REP(i,1,M) u=read(),v=read(),adde(u,v); REP(i,1,P) { u=read();vis[u]=false; qwq(u) vis[o->to]=false; } dfs(1); int ans=N; REP(i,1,N) if(V[i]) ans--; printf("%d\n",ans); return 0; }
bzoj1576:由于最短路唯一。所以有最短路径树。未在树中的边u,v对于lca(u,v)以下的点,有dist[x]=dist[u]+dist[v]+val[u,v]-dist[x](与dist[x]无关。可以将dist[u]+dist[v]+val[u,v]排序,依次更新。由于先更新的必定更优,于是可以用并查集压缩路径。
#include<cstdio> #include<cstring> #include<iostream> #include<algorithm> #include<queue> using namespace std; #define REP(i,s,t) for(int i=s;i<=t;i++) #define dwn(i,s,t) for(int i=s;i>=t;i--) #define clr(x,c) memset(x,c,sizeof(x)) #define qwq(x) for(edge *o=head[x];o;o=o->next) int read(){ int x=0;char c=getchar(); while(!isdigit(c)) c=getchar(); while(isdigit(c)) x=x*10+c-‘0‘,c=getchar(); return x; } const int nmax=100005; const int maxn=400005; const int inf=0x7f7f7f7f; struct edge{ int to,dist;edge *next; }; edge edges[maxn],*pt,*head[nmax]; int d[nmax],dep[nmax],fa[nmax],ans[nmax]; void adde(int u,int v,int d){ pt->to=v;pt->dist=d;pt->next=head[u];head[u]=pt++; pt->to=u;pt->dist=d;pt->next=head[v];head[v]=pt++; } struct node{ int x,d; node(int x,int d):x(x),d(d){} bool operator<(const node&rhs) const{ return d>rhs.d;} }; priority_queue<node>q; void dijkstra(){ clr(d,0x7f);d[1]=0;dep[1]=0; q.push(node(1,0)); while(!q.empty()){ node tmp=q.top();q.pop(); if(d[tmp.x]!=tmp.d) continue; qwq(tmp.x) if(d[o->to]>d[tmp.x]+o->dist){ d[o->to]=d[tmp.x]+o->dist; dep[o->to]=dep[tmp.x]+1;fa[o->to]=tmp.x; q.push(node(o->to,d[o->to])); } } } struct zc{ int from,to,dist; bool operator<(const zc&rhs) const{ return dist<rhs.dist;} }; zc zcs[maxn]; void getdep(int x){ } int update(int u,int v,int val){ if(u==v) return u; if(dep[u]<dep[v]) swap(u,v); if(ans[u]==-1) ans[u]=val-d[u]; return fa[u]=update(fa[u],v,val); } int main(){ clr(head,0);pt=edges; int N=read(),M=read(),u,v,dd; REP(i,1,M) { u=read(),v=read(),dd=read(),adde(u,v,dd); zc &oo=zcs[i];oo.from=u,oo.to=v,oo.dist=dd; } dijkstra(); REP(i,1,N) printf("%d:%d\n",i,dep[i]); int cnt=0; REP(i,1,M) { zc &oo=zcs[i]; if(d[oo.from]==d[oo.to]+oo.dist||d[oo.to]==d[oo.from]+oo.dist) continue; zc &ee=zcs[++cnt]; ee.from=oo.from,ee.to=oo.to,ee.dist=d[oo.from]+d[oo.to]+oo.dist; } sort(zcs+1,zcs+cnt+1); clr(ans,-1); REP(i,1,cnt) update(zcs[i].from,zcs[i].to,zcs[i].dist); REP(i,2,N) printf("%d\n",ans[i]); return 0; }
bzoj1585:建图后最小割就可以了。(由于没有处理第一个点的情况WA了一次
#include<cstdio> #include<cstring> #include<iostream> #include<algorithm> using namespace std; #define REP(i,s,t) for(int i=s;i<=t;i++) #define clr(x,c) memset(x,c,sizeof(x)) int read(){ int x=0;char c=getchar(); while(!isdigit(c)) c=getchar(); while(isdigit(c)) x=x*10+c-‘0‘,c=getchar(); return x; } const int nmax=10005; const int maxn=200005; const int inf=0x7f7f7f7f; struct edge{ int to,cap;edge *next,*rev; }; edge edges[maxn],*pt,*head[nmax],*cur[nmax],*p[nmax]; void add(int u,int v,int d){ pt->to=v;pt->cap=d;pt->next=head[u];head[u]=pt++; } void adde(int u,int v,int d){ add(u,v,d);add(v,u,0);head[u]->rev=head[v];head[v]->rev=head[u]; } int cnt[nmax],h[nmax]; int maxflow(int s,int t,int n){ clr(cnt,0);cnt[0]=n;clr(h,0); int flow=0,a=inf,x=s;edge *e; while(h[s]<n){ for(e=cur[x];e;e=e->next) if(e->cap>0&&h[x]==h[e->to]+1) break; if(e){ a=min(a,e->cap);cur[x]=p[e->to]=e;x=e->to; if(x==t){ while(x!=s) p[x]->cap-=a,p[x]->rev->cap+=a,x=p[x]->rev->to; flow+=a,a=inf; } }else{ if(!--cnt[h[x]]) break; h[x]=n; for(e=head[x];e;e=e->next) if(e->cap>0&&h[x]>h[e->to]+1) h[x]=h[e->to]+1,cur[x]=e; cnt[h[x]]++; if(x!=s) x=p[x]->rev->to; } } return flow; } bool vis[nmax]; int main(){ clr(head,0);pt=edges;clr(vis,false); int N=read(),M=read(),P=read(),s=0,t=N+N+1; adde(s,1,inf); REP(i,1,M){ int u=read(),v=read(); adde(u+u,v+v-1,inf);adde(v+v,u+u-1,inf); } REP(i,1,P){ int u=read();vis[u]=true; } adde(1,2,inf); REP(i,2,N){ if(vis[i]) adde(i+i-1,i+i,inf),adde(i+i,t,inf); else adde(i+i-1,i+i,1); } printf("%d\n",maxflow(s,t,t+1)); return 0; }
bzoj1589:tarjan缩点后乱搞即可。(读入优化x=x*1+c-‘0‘,由于自己出的都是小数据所以没有发现WA了一次。
#include<cstdio> #include<cstring> #include<iostream> #include<algorithm> #include<stack> using namespace std; #define REP(i,s,t) for(int i=s;i<=t;i++) #define dwn(i,s,t) for(int i=s;i>=t;i--) #define clr(x,c) memset(x,c,sizeof(x)) #define qwq(x) for(edge *o=head[x];o;o=o->next) int read(){ int x=0;char c=getchar(); while(!isdigit(c)) c=getchar(); while(isdigit(c)) x=x*10+c-‘0‘,c=getchar(); return x; } const int nmax=200005; const int maxn=400005; const int inf=0x7f7f7f7f; struct edge{ int to;edge *next; }; edge edges[maxn],*pt,*head[nmax]; void add(int u,int v){ pt->to=v;pt->next=head[u];head[u]=pt++; } int sccno[nmax],scc[nmax],pre[nmax],scc_cnt,dfs_clock=0; stack<int>s; int dfs(int x){ int lowu=pre[x]=++dfs_clock; s.push(x); qwq(x){ int to=o->to; if(!pre[to]) lowu=min(lowu,dfs(to)); else if(!sccno[to]) lowu=min(lowu,pre[to]); } if(lowu==pre[x]){ scc_cnt++;scc[scc_cnt]=0; while(1){ int tmp=s.top();s.pop(); sccno[tmp]=scc_cnt;scc[scc_cnt]++; if(tmp==x) break; } } return lowu; } int sum[nmax]; int getsum(int x){ if(sum[x]) return sum[x]; int ans=scc[x]; qwq(x) ans+=getsum(o->to); return ans; } int main(){ clr(head,0);pt=edges; int N=read(),u; REP(i,1,N) u=read(),add(i,u); scc_cnt=N; REP(i,1,N) if(!pre[i]) dfs(i); REP(i,1,N) qwq(i) if(sccno[i]!=sccno[o->to]) add(sccno[i],sccno[o->to]); REP(i,N+1,scc_cnt) sum[i]=getsum(i); REP(i,1,N) printf("%d\n",sum[sccno[i]]); return 0; }
summary:
1.各种神奇的错误方式。。。
2.自己出的数据也不要太小。。。但也不要自己被自己出的数据绕晕了。。。
时间: 2024-10-10 00:27:01