Usaco/the First Wave

bzoj1572: Greedy. First sort by chronological order, and then use the priority queue, if the time does not contradict directly inserted, otherwise determine the queue w smallest element is replaced. (I didn't use llwa once.

#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&AMP;RHS) const{return num<rhs.num;}}; Node nodes[nmax];struct node{int num,w;bool operator< (const NODE&AMP;RHS) const{return w>rhs.w;}}; Node Nodes[nmax];p riority_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&LT;O.W) Q.pop (), Q.push (o);} ll Ans=0;while (!q.empty ()) Ans+=q.top (). W,q.pop ();p rintf ("%Lld\n ", ans); return 0;} 

bzoj1574: Greedy, remove the unreachable points from the connected point set, and then Dfs. (two array names are the same as re once

#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);p T=edges;int read () {int X=0;char C=getchar (); while (!isdigit (c)) C=getchar () and 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++;p t->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--;p rintf ("%d\n", ans); return 0;} 

bzoj1576: Because the shortest path is unique. So there is the shortest path tree. Edges that are not in the tree are u,v for points below the LCA (U,V), with Dist[x]=dist[u]+dist[v]+val[u,v]-dist[x] (unrelated to dist[x). You can sort dist[u]+dist[v]+val[u,v] and update it sequentially. Because the first update must be better, so you can use and check the set of compressed path.

#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 () and 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++;p t->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&AMP;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&AMP;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);p t=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: The minimum cut is possible after the map is built. (Because the first point is not processed, WA once

#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 () and 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- &GT;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);p t=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 after shrinking points. (Read-in optimization x=x*1+c-' 0 ', because it's all small data, so I didn't find WA once.)

#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 () and 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);p t=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. A variety of magical wrong ways ...

2. Do not make your own data too small ... But do not be yourself out of the data around the halo ...

Usaco/the First Wave