每日刷题（第三天）

c++

class Solution {
public:
    #define mod 1000000007;
    int f[110];
   
    int numWays(int n) {
        f[0] = f[1] =1;
        for(int i = 2; i <= n; ++i )
        {
            f[i] = (f[i-1] + f[i-2] )% mod;
        }
        return f[n];
    }
};

c++

class Solution {
public:
    int f[110];
    int climbStairs(int n) {
        f[0] = f[1] = 1;
        for(int i = 2;i <= n; i++)
        {
            f[i] = f[i-1] + f[i-2];
        }
        return f[n];
    }
};

c++

class Solution {
public:
    #define maxn 1000001
    int f[maxn];
    int numberOfSteps(int num) {
        f[0] = 0;
        for(int i = 1;i <= num;++i)
        {
            if(i % 2 ==1)
            {
                f[i] = f[i-1] + 1;
            }
            else
            {
                f[i] = f[i/2] + 1;
            }
        }
        return f[num];
    }
};

c++

class Solution {
public:
    #define maxn 1024
    int f[maxn];
    int minCostClimbingStairs(vector& cost) {
        f[0] = f[1] = 0;
        for(int i = 2; i <= cost.size();i++)
        {
            f[i] = min((f[i-1]+cost[i-1]),(f[i-2]+cost[i-2]));
        }
        return f[cost.size()];
    }
};

c++

class Solution {
public:
    #define maxn 1024
    int f[maxn];
    int minCostClimbingStairs(vector& cost) {
        f[0] = f[1] = 0;
        int n = cost.size();
        for(int i = 2;i <= n;++i)
        {
            f[i] = min((f[i-1]+cost[i-1]),(f[i-2]+cost[i-2]));
        }
        return f[n];
    }
};