[Leetcode] Minimum Path Sum

Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path.

Note: You can only move either down or right at any point in time.

水

class Solution {
public:
    int minPathSum(vector<vector<int> > &grid) {
        int m = grid.size();
        int n = grid[0].size();
        for (int i = 0; i < m; ++i) {
            for (int j = 0; j < n; ++j) {
                if (i == 0 && j != 0) {
                    grid[i][j] += grid[i][j-1];
                } 
                if (i != 0 && j == 0) {
                    grid[i][j] += grid[i-1][j];
                }
                if (i != 0 && j != 0) {
                    grid[i][j] += min(grid[i-1][j], grid[i][j-1]);
                }
            }   
        }
        return grid[m-1][n-1];
    }
};