题解见：http://ecustacm.cn/contest/11/announcements
#include<bits/stdc++.h> #define rep(i,a,b) for(int i=a;i<=b;i++) using namespace std; const int maxn=2000010; int a[maxn],ans; char c[maxn]; int main() { int T,N,A,B,C,D,Ca=0; scanf("%d",&T); while(T--){ scanf("%s",c+1); N=strlen(c+1); A=B=C=D=0; rep(i,1,N){ if(c[i]=='4') A++; if(c[i]=='7') B++; if(i<N&&c[i]=='4'&&c[i+1]=='7') C++; if(i<N&&c[i]=='7'&&c[i+1]=='4') D++; } printf("Case %d: %d %d %d %d ",++Ca,A,B,C,D); } return 0; }
B
#include<bits/stdc++.h> #define rep(i,a,b) for(int i=a;i<=b;i++) using namespace std; const int maxn=2000010; char c[maxn]; int main() { int T,A,B,C,D,Ca=0; scanf("%d",&T); while(T--){ scanf("%d%d%d%d",&A,&B,&C,&D); printf("Case %d: ",++Ca); if(A<C||A<D||B<C||B<D||abs(C-D)>1) { puts("-1"); continue;} if(B==0){ rep(i,1,A) putchar('4'); puts(""); } else if(A==0){ rep(i,1,B) putchar('7'); puts(""); } else if(C==D){ int ta=C+1,tb=D; if(A<ta||B<tb){ ta=C,tb=C+1; if(A<ta||B<tb){ puts("-1"); continue;} putchar('7'); rep(i,1,C){ putchar('4'); if(i==1){ rep(j,1,A-ta) putchar('4'); } if(i==C){ rep(j,1,B-tb) putchar('7'); } putchar('7'); } puts(""); } else { rep(i,1,A-ta) putchar('4'); rep(i,1,C) putchar('4'),putchar('7'); rep(i,1,B-tb) putchar('7'); putchar('4'); puts(""); } } else if(C==D+1){ int ta=C,tb=C; if(A<ta||B<tb){ puts("-1"); continue;} rep(i,1,A-ta) putchar('4'); rep(i,1,C) putchar('4'),putchar('7'); rep(i,1,B-tb) putchar('7'); puts(""); } else if(D==C+1){ int ta=D,tb=D; if(A<ta||B<tb){ puts("-1"); continue;} //cout<<D<<" "<<A-ta<<" "<<B-tb<<endl; rep(i,1,D){ putchar('7'); if(i==1) { rep(j,1,A-ta) putchar('4'); } if(i==D) { rep(j,1,B-tb) putchar('7'); } putchar('4'); } puts(""); } } return 0; }
C
#include<bits/stdc++.h> #define rep(i,a,b) for(int i=a;i<=b;i++) using namespace std; const int maxn=2000010; char c[maxn]; struct SAM { int ch[maxn][2],fa[maxn],maxlen[maxn],cnt,last; void init() { cnt=1; last=1; memset(ch[1],0,sizeof(ch[1])); } void add(int x) { int np=++cnt,p=last; last=np; maxlen[cnt]=maxlen[p]+1; memset(ch[np],0,sizeof(ch[np])); while(p&&!ch[p][x])ch[p][x]=np,p=fa[p]; if(!p) fa[np]=1; else { int q=ch[p][x]; if(maxlen[q]==maxlen[p]+1) fa[np]=q; else { int nq=++cnt; maxlen[nq]=maxlen[p]+1; memcpy(ch[nq],ch[q],sizeof(ch[q])); fa[nq]=fa[q], fa[q]=fa[np]=nq; while(p&&ch[p][x]==q) ch[p][x]=nq,p=fa[p]; } } } }S; int q[maxn],pos[maxn],pre[maxn],head; int fcy,tail,ans[maxn]; int main() { int T,N,Ca=0; scanf("%d",&T); while(T--){ scanf("%d%s",&N,c+1); S.init(); rep(i,1,N) S.add(c[i]=='4'?0:1); head=tail=0; q[++head]=1; pos[head]=1; pre[head]=0; while(tail<head){ int u=q[++tail]; q[++head]=S.ch[u][0]; pos[head]=0; pre[head]=tail; if(!S.ch[u][0]) { fcy=head; break; } q[++head]=S.ch[u][1]; pos[head]=1; pre[head]=tail; if(!S.ch[u][1]) { fcy=head; break; } } int tot=0; while(fcy>1){ ans[++tot]=pos[fcy]; fcy=pre[fcy]; } printf("Case %d: %d ",++Ca,tot); for(int i=tot;i>=1;i--) putchar(ans[i]?'7':'4'); puts(""); } return 0; }
D
#include<bits/stdc++.h> #define rep(i,a,b) for(int i=a;i<=b;i++) using namespace std; const int maxn=2000010; int main() { int T,N,M,Ca=0,ans; scanf("%d",&T); while(T--){ scanf("%d%d",&N,&M); ans=max(N,M); ans=max(ans,(N*M+1)/2); if(N>M) swap(N,M); if(N==2) { int res=M/4*4; if(M%4==1) res+=2; if(M%4>=2) res+=4; ans=max(ans,res); } printf("Case %d: %d ",++Ca,ans); } return 0; }
E
#include<bits/stdc++.h> #define rep(i,a,b) for(int i=a;i<=b;i++) using namespace std; const int maxn=1000010; bitset<maxn>A,B; int main() { int N,L,R,x,ans; A[0]=1; scanf("%d",&N); rep(i,1,N){ scanf("%d%d",&L,&R); B.reset(); rep(j,L,R){ x=j*j; B|=(A<<x); } A=B; } ans=A.count(); printf("%d ",ans); return 0; }
F
#include<bits/stdc++.h> #define rep(i,w,v) for(int i=w;i<=v;i++) using namespace std; const int maxn=260; const int maxm=1000010; int N,M,K,ans,a[maxn][maxn]; int Laxt[maxn],Next[maxm],To[maxm],cnt; int linke[maxn],vis[maxn]; void add(int u,int v) { Next[++cnt]=Laxt[u]; Laxt[u]=cnt;To[cnt]=v; } bool find(int u) { for(int i=Laxt[u];i;i=Next[i]){ int v=To[i];if(vis[v]) continue; vis[v]=1; if(!linke[v]||find(linke[v])){ linke[v]=u; return true; } } return false; } bool check(int Mid) { int res=0; cnt=0; memset(Laxt,0,sizeof(Laxt)); memset(linke,0,sizeof(linke)); rep(i,1,N) rep(j,1,M) if(a[i][j]<=Mid) add(i,j); rep(i,1,N){ memset(vis,0,sizeof(vis)); if(find(i)) res++; } return res>=K; } int main() { scanf("%d%d%d",&N,&M,&K); K=N+1-K; rep(i,1,N) rep(j,1,M) scanf("%d",&a[i][j]); int L=1,R=1000000000; while(L<=R){ int Mid=(L+R)>>1; if(check(Mid)) ans=Mid,R=Mid-1; else L=Mid+1; } printf("%d ",ans); return 0; }