POj 1163 DP

#include <iostream>
#include <string>
using namespace std;
int main()
{
int n, tri[101][101], dp[101][101], i, j, Max;
while (scanf("%d", &n) != EOF)
{
memset(tri, 0, sizeof(tri));
for (i = 1; i <= n; i++)
for (j = 1; j <= i; j++)
scanf("%d", &tri[i][j]);
memset(dp, 0, sizeof(dp));
//下往上推DP
//for (i = n; i > 0; i--)
//	for (j = 1; j <= i; j++)
//	{
//		dp[i][j] = max(dp[i+1][j], dp[i+1][j+1]) + tri[i][j];
//		//printf("i = %d j = %d dp[i][j] = %d\n", i, j, dp[i][j]);
//	}
//printf("%d\n", dp[1][1]);
//上往下推DP
for (i = 1; i <= n; i++)
for (j = 1; j <= i; j++)
{
dp[i][j] = tri[i][j] + max(dp[i-1][j-1], dp[i-1][j]);
//printf("i = %d j = %d dp[i][j] = %d\n", i, j, dp[i][j]);
}
//最大值都存在了最后一行, 查找最大值输出
//还是下往上推理解方便, 代码也好写
Max = -100000;
for (j = 1; j <= n; j++)
Max = Max > dp
[j] ? Max : dp
[j];
printf("%d\n", Max);
}
return 0;
}