Triangle---minimum path sum

class Solution:
    # @param triangle, a list of lists of integers
    # @return an integer
    def minimumTotal(self, triangle):
        depth=len(triangle)
        dp=[]
        if depth==0:
            return 0
        for i in range(depth):
            if i==0:
                dp.append([triangle[i][i]])
            else:
                for j in range(i):
                    if j==0 :
                        dp.append([triangle[i][j]+dp[i-1][j]])
                    else:
                        dp[i].append(min(dp[i-1][j],dp[i-1][j-1])+triangle[i][j])
                dp[i].append(triangle[i][i]+dp[i-1][i-1])
        return min(dp[depth-1])