HDU-1176（基础方程DP）

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;

int f[100007][17];
int num[100007][17];

int max(int a,int b)
{
 return a>b?a:b;
}
int main()
{
 int n;
 int tm = 0;
 int tt;
 int x,T;
 while(scanf("%d",&n) && n)
 {
  memset(num,0,sizeof(num));
  memset(f,0,sizeof(f));
  for(int i = 1;i <= n;i++) {
   scanf("%d%d",&x,&T);
   num[T][x]++;
   tm = T>tm?T:tm;
  }
  f[1][4] = num[1][4];
  f[1][5] = num[1][5];
  f[1][6] = num[1][6];
  for(int i = 2;i <= tm;i++)
   for(int j = 0;j <= 10;j++)
    f[i][j] = max(max(f[i-1][j],f[i-1][j-1]),f[i-1][j+1])+num[i][j];
  tt = 0;
  for(int i = 0;i <= 10;i++)
   tt = f[tm][i]>tt?f[tm][i]:tt;
  printf("%d\n",tt);
 }
 return 0;
}