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.
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.
class Solution { public: int minimumTotal(vector<vector<int> > &triangle) { // Start typing your C/C++ solution below // DO NOT write int main() function int n = triangle.size(); if (!n) return 0; int *sum = new int[n]; sum[0] = triangle[0][0]; for (int i = 1; i < n; ++i) { for (int j = i; j >= 0; --j) { if (j != 0 && j != i) { sum[j] = min(sum[j - 1], sum[j]) + triangle[i][j]; } else if (j == i) { sum[j] = sum[j - 1] + triangle[i][j]; } else { sum[j] = sum[j] + triangle[i][j]; } } } int m = sum[0]; for (int i = 1; i < n; ++i) if (sum[i] < m) m = sum[i]; delete[] sum; return m; } };
No comments:
Post a Comment