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.

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