USACO Section 1.1 题解
为了备战2011NOIp，我决定把USACO重新刷过，练代码感觉，顺便回顾以前学的算法。
我觉得USACO的题十分好十分强大十分给力，每做一次感觉都不同，比赛前刷刷USACO是最好的选择。
我最支持USACO这种进阶模式，像我刷RQNOJ时，毫无目的的刷题，刷到哪算哪，不会的跳过，搞的我一点激情都没...
记得以前刷USACO时，十分兴奋，基本没都久，第一章就刷完了，貌似之前快刷到第4章了，貌似被卡住了，之后就很久没做了
虽然，现在刷USACO没以前那么积极了，刷玩一题就想放松下玩玩，不过这样也好，反正是为了准备比赛，慢慢来嘛...其实有些题做过再做还是有提高的（说不定你曾看过题解，现在自己想出来了，这不是很大的提高吗？我自己貌似之前也看过题解吧....+.+）
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这一节主要考查代码能力，不详细说了....
USACO 1.1.1 Your Ride Is Here 你要乘坐的飞碟在这里
program ride(input,output);
const
a:array['A'..'Z'] of integer=(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26);
var
m1,m2,i:longint;
s1,s2:string;
procedure init;
begin
assign(input,'ride.in');
assign(output,'ride.out');
reset(input);
rewrite(output);
end;
procedure outit;
begin
close(input);
close(output);
end;
begin
init;
readln(s1);readln(s2);
m1:=1;m2:=1;
for i:=1 to length(s1) do
begin
m1:=m1*a[s1[i]];
if m1>47 then m1:=m1 mod 47;
end;
for i:=1 to length(s2) do
begin
m2:=m2*a[s2[i]];
if m2>47 then m2:=m2 mod 47;
end;
m1:=m1 mod 47; m2:=m2 mod 47;
if m1=m2 then writeln('GO')
else writeln('STAY');
outit;
end.
USACO 1.1.2 Greedy Gift Givers 贪婪的礼物送礼者
program gift1(input,output);
type
data=record
money:longint;
name:string;
end;
var
n,i,j,x,y,k:longint;
s:string;
a:array[1..100] of data;
procedure init;
begin
assign(input,'gift1.in');
assign(output,'gift1.out');
reset(input);
rewrite(output);
end;
procedure outit;
begin
close(input);
close(output);
end;
begin
init;
readln(n);
for i:=1 to n do readln(a[i].name);
for i:=1 to n do
begin
readln(s);
readln(x,y);
if (x<>0)and(y<>0) then
begin
k:=1;
while s<>a[k].name do inc(k);
dec(a[k].money,x-x mod y);
end;
for j:=1 to y do
begin
readln(s);
if x<>0 then
begin
k:=1;
while s<>a[k].name do inc(k);
inc(a[k].money,x div y);
end;
end;
end;
for i:=1 to n do writeln(a[i].name,' ',a[i].money);
outit;
end.
USACO 1.1.3 Friday the Thirteenth 黑色星期五
program friday(input,output);
const
month:array[0..1,1..12] of integer=((3,0,3,2,3,2,3,3,2,3,2,3),(3,1,3,2,3,2,3,3,2,3,2,3)); //月份都减去28了，0是平年，1是闰年
var
a:array[0..6] of integer;
i,k,j,h,n:longint;
procedure init;
begin
assign(input,'friday.in');
assign(output,'friday.out');
reset(input);
rewrite(output);
end;
procedure outit;
begin
close(input);
close(output);
end;
begin
init;
readln(n);h:=6;
for i:=1900 to 1900+n-1 do
begin
if (i mod 400=0) or ((i mod 100<>0) and (i mod 4=0)) then k:=1 else k:=0;
for j:=1 to 12 do
begin
inc(a[h]);
h:=(h+month[k,j]) mod 7;
end;
end;
writeln(a[6],' ',a[0],' ',a[1],' ',a[2],' ',a[3],' ',a[4],' ',a[5]);
outit;
end.
USACO 1.1.4Broken Necklace破碎的项链
program beads(input,output);
var
n,i,max,ans,k:longint;
ch:char;
s:ansistring; //在pascal中string只有255个字符，要用ansistring，其他语言不知道到要不要注意
procedure init;
begin
assign(input,'beads.in');
assign(output,'beads.out');
reset(input);
rewrite(output);
end;
procedure outit;
begin
close(input);
close(output);
end;
begin
init;
readln(n);
readln(s);
s:=s+s+s;
for i:=n+1 to n+n do
begin
ans:=0;
k:=i-1; //left
ch:='w';
while (ch='w')or(ch=s[k])or(s[k]='w') do
begin
inc(ans);
if s[k]<>'w' then ch:=s[k];
dec(k);
end;
k:=i; //right
ch:='w';
while (ch='w')or(ch=s[k])or(s[k]='w') do
begin
inc(ans);
if s[k]<>'w' then ch:=s[k];
inc(k);
end;
if ans>max then max:=ans;
if ans>n then begin max:=n; break;end;
end;
writeln(max);
outit;
end.