輸入一個無符號整數n，用最少的步驟將該數變為1，當n為偶數時可以採取的步驟是除2的形式，當n為奇數的時候可以採取加1或者減1的操作。

#include <math.h>
#include <iostream>

using namespace std;

int min(int a, int b) {
	if (a < b)
		return a;
	return b;
}

int get_pow(uint num) {
	if (num <= 1)
		return 0;
	int power = 0;
	while (0 == (num % 2)) {
		power++;
		num /= 2;
	}
	return power;
}

int get_step(uint num) {
	if (1 >= num)
		return 1;
	int step = 0;
	while (num > 1) {
		if (0 == (num % 2)) {
			step++;
			num /= 2;
		} else {
			int plus_pow = get_pow(num + 1);
			printf("num=%d,  plus_pow=%d\n", num, plus_pow);
			int minus_pow = get_pow(num - 1);
			printf("num=%d, minus_pow=%d\n", num, minus_pow);
			if (1 == plus_pow && 1 == minus_pow) {
				step += 1 + min(get_step(num - 1), get_step(num + 1));
				return step;
			} else if (plus_pow > minus_pow) {
				step += 1 + plus_pow;
				num = (num + 1) / ((int)pow(2.0, plus_pow));
			} else if (plus_pow < minus_pow) {
				step += 1 + minus_pow;
				num = (num - 1) / ((int)pow(2.0, minus_pow));
			}
		}
		if (3 == num) {
			step += 2;
			num = 1;
		}
	}
	if (0 == num)
		step += 1;
	return step;
}

int main(int argc, char* argv[]) {
	int num = 0;
	cin >> num;
	int step = get_step(num);
	cout << "step:" << step << endl;
	return 0;
}