DP最最经典的入门题~~~好吧~~我只是在往后面刷而已~~这章开头是介绍的二进制的说~~不知咋地第一道题居然是个毫无关系的DP....
Program:
/*
ID: zzyzzy12
LANG: C++
TASK: numtri
*/
#include<iostream>
#include<stdio.h>
#include<string.h>
#include<math.h>
#include<algorithm>
#include<queue>
using namespace std;
int dp[2][1005],n,i,k,p,x,ans;
int main()
{
freopen("numtri.in","r",stdin);
freopen("numtri.out","w",stdout);
scanf("%d",&n);
memset(dp,0,sizeof(dp));
k=0;
scanf("%d",&dp[0][1]);
for (p=2;p<=n;p++)
{
k=1-k;
scanf("%d",&x);
dp[k][1]=dp[1-k][1]+x;
for (i=2;i<p;i++)
{
scanf("%d",&x);
dp[k][i]=dp[1-k][i];
if (dp[k][i]<dp[1-k][i-1]) dp[k][i]=dp[1-k][i-1];
dp[k][i]+=x;
}
scanf("%d",&x);
dp[k][p]=dp[1-k][p-1]+x;
}
ans=0;
for (i=1;i<=n;i++) ans=ans>dp[k][i]?ans:dp[k][i];
printf("%d\n",ans);
return 0;
}