简介

自底部向上

使用回溯

超时算法

class Solution {
public:
    int minValue;
    void dfs(vector<vector<int>>& triangle, int value, int depth, int index){
        if(depth == triangle.size()){
            if(minValue > value){
                minValue = value;
            }
            return;
        }
        dfs(triangle, value + triangle[depth][index], depth + 1, index);
        dfs(triangle, value + triangle[depth][index], depth + 1, index + 1);
    }
    int minimumTotal(vector<vector<int>>& triangle) {
        if(triangle.size() == 0){
            return 0;
        }
        minValue = 100000;
        dfs(triangle, 0, 0, 0);
        return minValue;
    }
};

自底向上

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