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Minimum Sum Path.cpp
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Minimum Sum Path.cpp
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// PROBLEM :- https://leetcode.com/problems/minimum-path-sum/
// LEETCODE | MEDIUM | DP on GRID
// Solution :- T.C. O(N * M) S.C. O(1) -> as done In-Place
// At every position, we can come from either its upside, or its leftside.
// So at every position, choose the minimum of the two, and add to the current value.
// Note that in first column, we can come from its leftside only.
// Similarly in first row, we can come from upside only.
// Finally return grid[n - 1][m - 1] as answer.
class Solution {
public:
int minPathSum(vector<vector<int>>& grid) {
int n = grid.size();
int m = grid[0].size();
for(int i = 1 ; i < n ; i++){
grid[i][0] += grid[i - 1][0];
}
for(int j = 1 ; j < m ; j++){
grid[0][j] += grid[0][j - 1];
}
for(int i = 1 ; i < n ; i++){
for(int j = 1 ; j < m ; j++){
grid[i][j] += min(grid[i - 1][j] , grid[i][j - 1]);
}
}
return grid[n - 1][m - 1];
}
};