poj 1163 The Triangle

The Triangle

Time Limit: 1000MS		Memory Limit: 10000K
Total Submissions: 34047		Accepted: 20245

Description

7
3   8
8   1   0
2   7   4   4
4   5   2   6   5

(Figure 1)

Figure 1 shows a number triangle. Write a program that calculates the highest sum of numbers 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.

Input

Your program is to read from standard input. The first line contains one integer N: the number of rows in the triangle. The following N lines describe the data of the triangle. The number of rows in the triangle is > 1 but <= 100. The numbers in the triangle, all integers, are between 0 and 99.

Output

Your program is to write to standard output. The highest sum is written as an integer.

Sample Input

5
7
3 8
8 1 0 
2 7 4 4
4 5 2 6 5

Sample Output

30

讲解：其实就是说从上到下，求最优的的一组解，使得从上到下的和最大。每一行中只取一个，且是上下关联的，数字；

代码如下：

#include<iostream>
#include<cstring>
using namespace std;
int map[110][110];
int main()
{
  int i,j,n;
  while(cin>>n)
  {
      memset(map,0,sizeof(map));//初始化数组；
    for(i=1;i<=n;i++)
      for(j=1;j<=i;j++)
         cin>>map[i][j];
    for(i=n-1;i>=1;i--)
      for(j=1;j<=i;j++)
         map[i][j]=max(map[i][j]+map[i+1][j],map[i][j]+map[i+1][j+1]);//判断这个节点下面的两个子节点，取最大的一个；
     cout<<map[1][1]<<endl;
  }
  return 0;
}