Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below.
For example, given the following triangle
[
[2],
[3,4],
[6,5,7],
[4,1,8,3]
]
The minimum path sum from top to bottom is 11 (i.e., 2 + 3 + 5 + 1 = 11).
Note:
Bonus point if you are able to do this using only O(n) extra space, where n is the total number of rows in the triangle.
public class Solution {
public int MinimumTotal(IList<IList<int>> triangle) {
int rows = triangle.Count();
for(int i=1;i<rows;i++){
for(int j=0;j<triangle[i].Count();j++){
if(j==0 || j == triangle[i].Count()-1){
if(j > triangle[i-1].Count()-1){
triangle[i][j]+=triangle[i-1][j-1];
}
else{
triangle[i][j]+=triangle[i-1][j];
}
}
else{
triangle[i][j] += Math.Min(triangle[i-1][j-1], triangle[i-1][j]);
}
}
}
int min = int.MaxValue;
for(int i=0;i<triangle[rows-1].Count();i++){
min = Math.Min(min, triangle[rows-1][i]);
}
return min;
}
}
Time Complexity: O(m*n)
Space Complexity: O(1)