深圳私人做网站,wordpress分类目录伪静态,wordpress链接在哪里设置密码,西安网站外包斐波那契数列是一个满足递推关系的数列#xff0c;如#xff1a;1 1 2 3 5 8 ... 其前两项为1#xff0c;第3项开始#xff0c;每一项都是其前两项之和。 用Go实现一个简单的斐波那契计算逻辑
func fib(n int) int {if n 1 || n 2 {return 1}return fib(n-1) fib(n-2)
…斐波那契数列是一个满足递推关系的数列如1 1 2 3 5 8 ... 其前两项为1第3项开始每一项都是其前两项之和。 用Go实现一个简单的斐波那契计算逻辑
func fib(n int) int {if n 1 || n 2 {return 1}return fib(n-1) fib(n-2)
}我们将其改进一下用更简单的方式描述同时把变量的定义提到前边并将返回的逻辑拿到函数末尾。
func fib1(n int) int {var tmp, res, res1, res2 intif n 1 {goto return1}if n 2 {goto return1}tmp n - 1res1 fib1(tmp)tmp n - 2res2 fib1(tmp)res res1 res2return res
return1:return 1
}继续改进
func fib2(n int) int {var tmp, res, res1, res2 intif n 1 {goto return1}if n 2 {goto return1}tmp ntmp - 1res1 fib2(tmp)tmp ntmp - 2res2 fib2(tmp)res res1res res2return res
return1:return 1
}继续改进复用变量
func fib3(n int) int {var res, res1 intif n 1 {goto return1}if n 2 {goto return1}res1 nres1 - 1res fib3(res1)res1 nres1 - 2res1 fib3(res1)res res1return res
return1:return 1
}继续改进
func fib4(r0 int) int {var r1, r2 intif r0 2 {goto return1}r2 r0r2 - 1r1 fib4(r2)r2 r0r2 - 2r2 fib4(r2)r1 r2return r1
return1:return 1
}汇编函数接口定义
func fib5(n int) int汇编函数实现
TEXT ·fib5(SB),$40-16MOVD R0, tmp-24(SP);MOVD R1, tmp-16(SP);MOVD R2, tmp-8(SP) // save contextMOVD n0(FP), R0; MOVD $0, R1; MOVD $0, R2 // R0: load value from stack memoryCMP $2, R0; BLE LABEL_RETURN1 // if R0 2 {goto LABEL_RETURN1}MOVD R0, R1; SUB $1, R1 // R1 R0 - 1MOVD R1, tmp-40(SP); CALL ·fib5(SB); MOVD tmp-32(SP), R1 // R1 fib5(R1)MOVD R0, R2; SUB $2, R2 // R2 R0 - 2MOVD R2, tmp-40(SP); CALL ·fib5(SB); MOVD tmp-32(SP), R2 // R2 fib5(R2)ADD R1, R2; MOVD R2, R0 // R0 R1 R2JMP LABEL_END
LABEL_RETURN1:MOVD $1, R0 // R0 1
LABEL_END:MOVD R0, n8(FP) // set return value: R0MOVD tmp-24(SP), R0; MOVD tmp-16(SP), R1; MOVD tmp-8(SP), R2 // recovery contextRET
结果
