LeetCode OJ--Triangle **

https://oj.leetcode.com/problems/triangle/

一个三角形，类似于杨辉三角的形状，求从上到下最小的路径和，但走每一步都得是相邻的。

动态规划，从下到上一层层来。

sum[i] = min{sum[i]+triangle[i][j],sum[i+1]+triangle[i][j]}

有一个保存每一个点数值的过程。

#include <iostream>
#include <vector>
using namespace std;

class Solution {
public:
    int minimumTotal(vector<vector<int> > &triangle) {
        int row = triangle.size();
        if(row == )
            return ;
        if(row == )
            return triangle[][];

        //initialize
        vector<int> sum;
        sum.resize(row);
        for(int i = ;i<triangle[row-].size();i++)
            sum[i] = triangle[row-][i];

        for(int i = row-;i>=;i--)
        {
            for(int j = ;j<=i;j++)
            {
                int min1 = sum[j]<sum[j+]?sum[j]:sum[j+];
                sum[j] = min1 + triangle[i][j];
            }
        }
        return sum[];
    }
};

int main()
{
    class Solution myS;
    vector<int> v1;
    v1.push_back(-);
    vector<int> v2;
    v2.push_back(-);
    v2.push_back(-);
    vector<int> v3;
    v3.push_back();
    v3.push_back();
    v3.push_back();
    vector<int> v4;
    v4.push_back();
    v4.push_back();
    v4.push_back();
    v4.push_back();

    vector<vector<int> > num;
    num.push_back(v1);
    num.push_back(v2);
    num.push_back(v3);
    num.push_back(v4);
    cout<<myS.minimumTotal(num);

    return ;
}