120. Triangle

三角里的每一个数都是保存的从根节点到这个节点最短的距离。我目前的方法答案是对的，但是修改了Triangle本身，其实可以多保存一个，但是我懒得改了哈哈

    public int minimumTotal(List<List<Integer>> triangle) {
        int level = triangle.size();
        List<Integer> res = new ArrayList<Integer>();
        res.add(triangle.get(0).get(0));
        for(int i = 1; i < level; i++) {
            List<Integer> curLevel = triangle.get(i);
            int len = curLevel.size();
            curLevel.set(0, curLevel.get(0) + res.get(0));
            for(int j = 1; j < len - 1; j++) {
                curLevel.set(j, Math.min(res.get(j-1), res.get(j)) + curLevel.get(j));
            }
            curLevel.set(len - 1, curLevel.get(len - 1) + res.get(len - 2));
            res = new ArrayList<Integer>(curLevel);
        }
        int min = Integer.MAX_VALUE;
        for(int i = 0; i < res.size(); i++) {
            min = (min < res.get(i))? min: res.get(i);
        }
        return min;
    }