《程序设计与算法（二）算法基础》《第六周 分治》动态规划

/*
http://bailian.openjudge.cn/practice/1163/
1163:The Triangle
递归解法2：数字三角形的记忆递归型动归程序
*/
#include<iostream>
#include<algorithm>
#define MAX 101
using namespace std;
int D[MAX][MAX];
int sum[MAX][MAX];
int n;
int MaxSum(int i, int j)
{
    if (sum[i][j] != -1)/*说明这个路径的最大和已经算过了*/
    {
        return sum[i][j];
    }
    if (i == n)
    {
        sum[i][j] = D[i][j];
    }
    else
    {
        int x = MaxSum(i + 1, j);
        int y = MaxSum(i + 1, j + 1);
        sum[i][j] = max(x, y) + D[i][j];
    }
    return sum[i][j];
}
int main()
{
    int i, j;
    cin >> n;
    for (i = 0; i < n; i++)
    {
        for (j = 0; j <= i; j++)
        {
            cin >> D[i][j];
            sum[i][j] = -1;
        }
    }
    cout << MaxSum(0, 0) << endl;
    return 0;

}