leetcode-120-Triangle

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描述

Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below.

For example, given the following triangle

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[
     [2],
    [3,4],
   [6,5,7],
  [4,1,8,3]
]

The minimum path sum from top to bottom is 11 (i.e., 2 + 3 + 5 + 1 = 11).

分析

其实这个三角形这样写会比较容易思考： 

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[
[2],
[3,4],
[6,5,7],
[4,1,8,3]
]

最基础的动态规划的题目了，从下往上递推，公式为：triangle[i][j] += min(triangle[i+1][j], triangle[i+1][j+1]);

解决方案1(C++)

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

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