10151 - 数字金字塔
考虑在下面被显示的数字金字塔。 写一个程序来计算从最高点开始在底部任意处结束的路径经过数字的和的最大。 每一步可以走到左下方的点也可以到达右下方的点。 7
3 8
8 1 0
2 7 4 4
4 5 2 6 5 在上面的样例中,从7 到 3 到 8 到 7 到 5 的路径产生了最大和:30
Input
第一个行包含 R(1<= R<=1000) ,表示行的数目。 后面每行为这个数字金字塔特定行包含的整数。 所有的被供应的整数是非负的且不大于100。
Output
单独的一行包含那个可能得到的最大的和。
Examples
Input
5 7 3 8 8 1 0 2 7 4 4 4 5 2 6 5
Output
30
Hint
Number Triangles Consider the number triangle shown below. Write a program that calculates the highest sum of numbers that can be passed on a route that starts at the top and ends somewhere on the base. Each step can go either diagonally down to the left or diagonally down to the right.
7
3 8
8 1 0
2 7 4 4
4 5 2 6 5
In the sample above, the route from 7 to 3 to 8 to 7 to 5 produces the highest sum: 30.
PROGRAM NAME: numtri INPUT FORMAT The first line contains R (1 <= R <= 1000), the number of rows. Each subsequent line contains the integers for that particular row of the triangle. All the supplied integers are non-negative and no larger than 100. SAMPLE INPUT (file numtri.in) 5 7 3 8 8 1 0 2 7 4 4 4 5 2 6 5
OUTPUT FORMAT A single line containing the largest sum using the traversal specified. SAMPLE OUTPUT (file numtri.out) 30