triangle（三角形）——leetcode

题目如下：
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 is11(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.

题解如下：

public static int minimumTotal(ArrayList> triangle) {
    int []d=new int [1];
    d[0]=triangle.get(0).get(0).intValue();
    for(int i=1;iint min=Integer.MAX_VALUE;
    for(int i=0;iif(min>d[i]) {
            min=d[i];
        }
    }
    return min;
}
public static int [] dp(int []d,ArrayList> triangle,int now) {
    int []p=new int [d.length+1];
    p[0]=d[0]+triangle.get(now).get(0).intValue();
    p[now]=d[now-1]+triangle.get(now).get(now).intValue();
    for(int j=1;jint min=d[j-1];
        if(d[j]get(now).get(j).intValue();
    }
    return p;
}