Pascal高精度快速開(kāi)方

1、開(kāi)方運(yùn)算，高精度冪（程序中為Power），Longint指數(shù)（程序中為Exp），求底。估計(jì)底數(shù)范圍后采用2分查找，速度很快。測(cè)試數(shù)據(jù)：111 /指數(shù) /冪/這個(gè)數(shù)據(jù)據(jù)說(shuō)是以前一個(gè)人（叫什么Shakuntala Devi，谷歌一下）和電腦PK運(yùn)算速度的測(cè)試數(shù)據(jù)，結(jié)果電腦輸了，不爽，用這個(gè)程序重振電腦雄風(fēng)，保證比那人快多了。type ltype=array 0.1000 of word;const enum:array 1.9 of longint=(16,128,1024,16384,131072,1048576,16777216,134217728,1073741824);var pwr,cp

2、wr:ltype; exp,bse:longint; ta:ansistring;function ttltype(a:ansistring):ltype; /Convert Ansistring to LTypevar i:longint; c:ltype;begin c0:=length(a); for i:=1 to c0 do ci:=ord(ac0-i+1)-48; ttltype:=c;end;function ttltype(a:longint):ltype; /Convert String to LTypevar i:longint; c:ltype;begin c0:=0;

3、i:=a; while i<>0 do begin cc0+1:=i mod 10; i:=i div 10; c0:=c0+1; end; ttltype:=c;end;function ttString(a:ltype):string; /Convert LType to Stringvar i:longint; c:string;begin c:='' for i:=a0 downto 1 do c:=c+chr(ai+48); ttString:=c;end;function multiply(a,b:ltype):ltype; /High_Multiply

4、var c:ltype; t,i,j:longint;begin fillchar(c0,sizeof(c),0); c0:=a0+b0+1; for i:=1 to a0 do for j:=1 to b0 do begin inc(ci+j-1,ai*bj mod 10); ci+j:=ci+j+(ai*bj div 10)+(ci+j-1 div 10); ci+j-1:=ci+j-1 mod 10; end; while cc0=0 do dec(c0); multiply:=c;end;function getpwr(bse:longint):ltype; /Calculate Po

5、wer <Pinyin:Mi,Di 4 Sheng>var c,nbse:ltype; i:longint;begin nbse:=ttltype(bse); c:=nbse; for i:=2 to exp do c:=multiply(nbse,c); getpwr:=c;end;function chkbig:word; /Compare Powervar i:longint; c:word;begin /cpwr > pwr -> 2 /cpwr < pwr -> 0 /cpwr = pwr -> 1 c:=1; /Normal State,I

6、f pwr=cpwr Then Never Change if cpwr0>pwr0 then /Compare Length <pwr0=length(pwr)> c:=2 else if cpwr0<pwr0 then c:=0 else /Compare Digits for i:=cpwr0 downto 1 do if cpwri>pwri then begin c:=2; break; end else if cpwri<pwri then begin c:=0; break; end; chkbig:=c;end;procedure op(a:

7、longint); /Outputbegin writeln(a); close(input); close(output); halt;end;procedure run(b,e:longint); /Main Procedure,Binary Search <Pinyin:2 Fen Chazhao>var a,i:longint; c:ltype;begin if b=e then op(b); a:=(b+e) div 2; cpwr:=getpwr(a); i:=chkbig; if i=2 then /Compare,Current (Temporary) Power

8、> Real (Input From File) Power run(b,a) else if i=0 then /Compare,Current (Temporary) Power < Real (Input From File) Power run(a+1,e) else op(a); /Compare,Current (Temporary) Power = Real (Input From File) Power,OK!end;procedure calc;var bl:longint;begin bl:=pwr0 div exp+1; /Estimate Length of Result run(1,enumbl); /Bigger & Nearest Power of 2,Example:4 Digits->16384 <216>end;begin assign(input,'Num.txt'); assign(output,'NumOut.txt&