Tyvj三周年邀请赛

A 迷路的VariantF (P2011)

        没什么好说的，把bit打包到byte里，其实我以前一直以为boolean是1 bit。比赛的时候写挂了。

var  n,i,j,h,t:integer;
    dis,Q:array[1..1000] of integer;
    map:array[0..125000] of byte;
    ch:char;
procedure setbit(u,v:longint);
          var t:longint;
          begin
          t:=(u-1)*n+v;
          map[t>>3]:=map[t>>3] or(1<<(t and 7));
          end;
function getbit(u,v:longint):boolean;
         var t:longint;
         begin
         t:=(u-1)*n+v;
         if((map[t>>3]>>(t and 7))and 1)=1
           then exit(true)
           else exit(false);
         end;
begin
readln(N);
for i:=1 to N do
  begin
  dis[i]:=-1;
  for j:=1 to N do
    begin
    read(ch);
    if(ord(ch)<>ord('0'))
      then setbit(i,j);
    end;readln;end;
h:=0;t:=1;Q[1]:=1;dis[1]:=0;
while h<t do begin
  inc(h);
  for i:=1 to n do begin
    if(getbit(Q[h],i))
      and(dis[i]=-1)
      then begin
           dis[i]:=dis[Q[h]]+1;
           inc(t);Q[t]:=i;
           end;end;end;
writeln(dis[n]);
end.

B 矩阵交换 (P2012)

        行列不影响。乱搞。

program mc;
const maxn=700;
var A:array[1..maxn,1..maxn] of longint;
    R,C:array[1..maxn] of longint;
    i,j,n,k,x,y:longint;
    ch:char;
procedure swap(var x,y:longint);
var t:longint;begin t:=x;x:=y;y:=t;end;
begin
readln(n,k);
for i:=1 to n do begin
  for j:=1 to n do
    read(A[i][j]);
  readln;R[i]:=i;C[i]:=i;
  end;
while k>0 do begin
  readln(ch,x,y);
  case ch of
    'A':writeln(A[R[x]][C[y]]);
    'R':swap(R[x],R[y]);
    'C':swap(C[x],C[y]);
    end;
  dec(k);end;
end.

C 配对 (P2013)

        F[i]表示做i，序列长度为偶数的最大的权值，G[i]为奇数。50分做法。

        G[i]:=F[i-1]

        F[i]:=max(F[i-1](删掉B[i]),max{G[j]+A[j]*B[i](保留B[i])})

        斜率优化什么的无力了。

program pair;
uses math;
const maxn=1000000;
var f,g:array[0..maxn] of int64;
    A,B:array[1..maxn] of int64;
    ans:int64;
    i,j,n:longint;
begin
readln(n);
for i:=1 to n do read(A[i]);
for i:=1 to n do read(B[i]);
for i:=1 to n do begin
  G[i]:=F[i-1];F[i]:=F[i-1];
  for j:=0 to i-1 do
    F[i]:=max(G[j]+A[j]*B[i],F[i]);
  Ans:=max(F[i],ans);end;
writeln(ans);
end.

总结  200分还是很基础的，但是都写挂了，只有30分。要知道200分就排到25名了。敲之前要想清楚，写完代码要认真查错。