leetcode:Pow(x, n)

来源：互联网发布：什么是金蝶软件编辑：程序博客网时间：2024/05/22 00:45

Implement pow(x, n).

没有考虑INT_MIN 和 INT_MAX导致错了两次

贴上挫挫的代码

class Solution {public:    double pow(double x, int n) {if (x<0.0000001 && x>-0.000001 && n<0)return x;//it should be false;else if (x<0.0000001 && x>-0.000001)return x;else if(n==0)return 1;else if(x>-1.000001 && x<-0.999999){if(n&1)return x;return -x;}else if(x>0.999999 && x<1.000001)return x;int temp_n = n>0?n:-n;double result = pow_binary(x, temp_n);return  n>0?result:(1/result);    }private:double pow_binary(double x, int n){if(n==1)return x;else if(n==0)return 1;double result = pow_binary(x,n>>1);result = result*result;if(n&1)result = result*x;return result;}};

下面贴上大神代码，很优美，代码出处fengbingyang

class Solution {public:    double pow(double x, int n) {        // Start typing your C/C++ solution below        // DO NOT write int main() function        if(n<0){if(n==INT_MIN)return 1.0 / (pow(x,INT_MAX)*x);elsereturn 1.0 / pow(x,-n);}        if(n==0)            return 1.0;double ans = 1.0 ;for(;n>0; x *= x, n>>=1){if(n&1>0)ans *= x;}return ans;    }};

0 0