LeetCode 64. 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.

answer:

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

};