Leetcode 50.Pow (x, N) (n-th-square of X) thinking and method of solving problems

Pow (x, N)

Implement POW (x, N).

Idea: The topic is not difficult, but need to consider the situation is more.

The specific code is as follows:

public class Solution {public    double Mypow (double x, int n) {    Boolean isMin0 = true;//result minus    if (x > 0 | | (n&1) = = 0) {//x>0 or n is even    isMin0 = false;//is positive    }    x = x < 0?-x:x;//set x uniformly as positive        double d = 1.0;    if (n > 0) {//n in three cases            while (n > 0) {                d = d*x;                n--;            if ((Math.Abs (d-1.0) < 1e-15)) {            d = 1.0;//default equals 1 break            ;            } else if ((Math.Abs (d) < 1e-15)) {            d = 0;//default equals 0 break;}}    } else if (n = = 0) {    return 1;    } else{    while (n < 0) {    d = d/x;    n++;            if ((Math.Abs (d-1.0) < 1e-15)) {            d = 1;            break;            } else if ((Math.Abs (d) < 1e-15)) {            if (isMin0) {///divisor equals 0, will be equal to plus or minus infinity            return double.min_value;            } else{            return Double.max_value;}}}    return ismin0?-d:d;}    }

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Leetcode 50.Pow (x, N) (n-th-square of X) thinking and method of solving problems