joj2511: Number triangle

 2511: Number triangle

---

Result	TIME Limit	MEMORY Limit	Run Times	AC Times	JUDGE
	1s	65536K	467	233	Standard

        5

      3   4

    8   1   2

  5   4   3   6

2   1   7   9   8

A number trangle is composed of N(N<=100) line numbers, the i-th line contains i positive integers(<=100). A chess can walk from the top line of the triangle to the bottom line. Suppose the chess is on the k-th number of one line, then it can only move to the k-th number or the (k+1)-th number of the line below in one step. Find a path from the top to the bottom, which can maximize the sum of the integers on the path.

Input

There are multiple test cases.For each test case, there's an integer N representing the size of the triangle, followed by N lines of positive intergers, the first line has 1 integer, next has two integers... the Nth line has N integers.

Output

The maximum sum of the integers on the path.

Sample Input

3

5

7 0

2 4 3

3

2

6 1

2 3 9

Sample Output

16

12

 

Problem Source: xwbsw

 

---

This problem is used for contest: 120 

---

Submit / Problem List / Status / Discuss

 

水DP

倒着推即可

 

 1 #include <stdio.h>

 2 #include <string.h>

 3 

 4 int a[105][105];

 5 

 6 int main()

 7 {

 8     //freopen("in.txt", "r", stdin);

 9     

10     int n, i, j;

11     

12     while (scanf("%d", &n) == 1)

13     {

14         memset(a, 0, sizeof(a));

15         for (i=1; i<=n; ++i)

16         {

17             for (j=1; j<=i; ++j)

18             {

19                 scanf("%d", &a[i][j]);

20             }

21         }

22         

23         for (i=n; i>1; --i)

24         {

25             for (j=i; j>=1; --j)

26             {

27                 if(a[i][j]+a[i-1][j]>a[i][j+1]+a[i-1][j])

28                     a[i-1][j]=a[i][j]+a[i-1][j];

29                 else

30                     a[i-1][j]=a[i][j+1]+a[i-1][j];

31             }

32         }

33         printf("%d\n", a[1][1]);

34     }

35     

36     return 0;

37 }