C++ algorithm learning (greedy algorithm)

1. Goal

Without considering the overall optimality, the algorithm obtains a local optimal solution in a certain sense .

2. Method

1. Divide the solved problem into several sub-problems
2. Solve each sub-problem to obtain the local optimal solution
of the sub-problem 3. Combine the local optimal solution of the sub-problem into a solution of the original problem

3. Examples

122. The Best Time to Buy and Sell Stocks II

class Solution {
    
    
public:
    int maxProfit(vector<int>& prices) {
    
    
        int answer = 0;
        if(prices.size() < 2) return 0;
        //每次都找当下可以赚钱的
        for(int i = 0;i < prices.size() - 1;i++){
    
    
            int diff = prices[i+1] - prices[i];
            if(diff > 0) answer += diff;
        }
        return answer;
    }
};