Day 18 Minimum Path Sum Leetcode

30 day leetcode challenge

day 18 minimum path sum

Problem:

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.

Example:

Input:
[
  [1,3,1],
  [1,5,1],
  [4,2,1]
]
Output: 7
Explanation: Because the path 1→3→1→1→1 minimizes the sum.

explanation:

https://youtu.be/bGwYjXxF-ao

code:

class Solution {
public:
int minPathSum(vector<vector<int>>& grid) {

for(int i=0;i<grid.size();i++){
for(int j=0;j<grid[0].size();j++){
if(i-1>=0 && j-1>=0){
grid[i][j]+=min(grid[i-1][j],grid[i][j-1]);
}
else{
if(i-1>=0){
grid[i][j]+=grid[i-1][j];
}
if(j-1>=0){
grid[i][j]+=grid[i][j-1];
}
}
}
}
return grid[grid.size()-1][grid[0].size()-1];
}
};