每日刷题（第一天）

c++

class Solution {
public:
    int sum(int num1, int num2) {
        return num1+num2;
    }
};

c++

class Solution {
public:
    int mySqrt(int x) {
        return (int)sqrt(x);
    }
};

c++

class Solution {
public:
    int mySqrt(int x) {
        return (int)sqrt(x);
    }
};

c++

class Solution {
public:
    bool isPerfectSquare(int num) {
        int ans = 0;
        for(int i =0;i <=num;i ++)
        {
            if((long long)i * i <=num)
            {
                ans = i;
            }
            else
            break;
        }
        return (long long)ans * ans ==num;
    }
};

c++

class Solution {
public:
    double myPow(double x, int n) {
        return pow(x,n); 
    }
};

c++

 class Solution {
public:
    double myPow(double x, int n) {
        return pow(x,n);
    }
};

c++

class Solution {
public:
    bool isPowerOfTwo(int n) {
        if(n <= 0)
        return false;
        else if(n == 1)
        return true;
        else{
            long long ans = 1;
            while(1)
            {
                ans *= 2;
                if(ans == n)
                return true;
                else if(ans > n)
                return false;

            }
            return false;
        }
    }
};

c++

class Solution {
public:
    bool isPowerOfThree(int n) {
        if(n <= 0)
        return false;
        else if(n == 1)
        return true;
        else {
            long long ans = 1;
            while(1)
            {
                ans *= 3;
                if(ans == n)
                return true;
                else if(ans > n)
                return false;
            }
            return false;
        }
    }
};

c++

class Solution {
public:
    bool isPowerOfThree(int n) {
        if(n <= 0)
        return false;
        else if(n == 1)
        return true;
        else {
            long long ans = 1;
            while(1)
            {
                ans *= 3;
                if(ans == n)
                return true;
                else if(ans > n)
                return false;
            }
            return false;
        }
    }
};

c++

class Solution {
public:
    vector swapNumbers(vector& numbers) {
        vector ret;
        ret.push_back(numbers[1]);
        ret.push_back(numbers[0]);
        return ret;
    }
};