UVAlive 7361 Immortal Porpoises（矩阵快速幂）

题目地址：https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=5383

思路：

type arr=array[1..2,1..2] of int64;var x,p:int64; a,b,c,w:arr; cas,i,t:longint;procedure mul(var a,b,c:arr);var i,j,k,n:longint;begin n:=2; fillchar(w,sizeof(w),0); for i:=1 to n do  for j:=1 to n do   for k:=1 to n do    w[i][j]:=(w[i][j]+a[i][k]*b[k][j]) mod p; for i:=1 to n do  for j:=1 to n do   c[i][j]:=w[i][j];end;begin readln(cas); p:=1000000000; for i:=1 to cas do begin   read(t);   readln(x);  a[1,1]:=0;a[1,2]:=1;a[2,1]:=0;a[2,2]:=0;  b[1,1]:=0;b[1,2]:=1;b[2,1]:=1;b[2,2]:=1;  while (x<>0) do   begin    if x mod 2=1 then mul(a,b,a);    x:=x div 2;    mul(b,b,b);   end;  write(t);  write(' ');  writeln(a[1][1]); end;end.