代码随想录算法训练营第33天

LeetCode 509. 斐波那契数列

链接

class Solution {
public:
    int fib(int n) {
        if(n == 0 || n == 1) {
            return n;
        }
        vector<int> dp(n + 1, 0);
        dp[0] = 0, dp[1] = 1;
        for(int i = 2; i <= n; i++) {
            dp[i] = dp[i-1] + dp[i-2];
        }
        return dp[n];
    }
};

LeetCode 70. 爬楼梯

链接

class Solution {
public:
    int climbStairs(int n) {
        if(n <= 2) {
            return n;
        }
        int dp[2] = {1, 1};
        for(int i = 2; i <= n; i++) {
            int sum = dp[0] + dp[1];
            dp[0] = dp[1];
            dp[1] = sum;
        }
        return dp[1];
    }
};

LeetCode 746. 使用最小花费爬楼梯

链接

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