解题思路和剑指offer47、leetcode62、leetcode63、leetcode120类似。
思路不多解释了，实现如下：
class Solution { public: int minPathSum(vector<vector<int>>& grid) { if (grid.empty() || grid[0].empty()) return 0; int rows = grid.size(); int cols = grid[0].size(); for (int i = 0; i < rows; ++i) { for (int j = 0; j < cols; ++j) { if (i == 0 && j == 0) continue; else if (i == 0) { grid[i][j] += grid[i][j-1]; } else if (j == 0) { grid[i][j] += grid[i-1][j]; } else { if (grid[i][j-1] < grid[i-1][j]) grid[i][j] += grid[i][j-1]; else grid[i][j] += grid[i-1][j]; } } } return grid.back().back(); } };