poj 1163 The Triangle

Time Limit: 1000MS		Memory Limit: 10000K
Total Submissions: 20040		Accepted: 11615

       本题相当的简单，就是简单的DP问题。从倒数第二层开始，每一层记录下上一层相邻最大的值，a[i][j]=max(a[i+1][j+1],a[i+1][j])+a[i][j]。a[1][1]即是所要求的值：

代码：

 

  
    

   
     
   
      1 
   
     #include
   
     <
   
     stdio.h
   
     >
   
     

   
      2 
   
      
   
     int
   
      max(
   
     int
   
      a,
   
     int
   
      b)

   
      3 
   
     {

   
      4 
   
      
   
     if
   
     (a
   
     >
   
     b)

   
      5 
   
      
   
     return
   
      a;

   
      6 
   
      
   
     return
   
      b;

   
      7 
   
     }

   
      8 
   
      
   
     int
   
      main()

   
      9 
   
     {

   
     10 
   
      
   
     int
   
      a[
   
     105
   
     ][
   
     105
   
     ],i,j,n;

   
     11 
   
      scanf(
   
     "
   
     %d
   
     "
   
     ,
   
     &
   
     n);

   
     12 
   
      
   
     for
   
     (i
   
     =
   
     1
   
     ;i
   
     <=
   
     n;i
   
     ++
   
     )

   
     13 
   
      
   
     for
   
     (j
   
     =
   
     1
   
     ;j
   
     <=
   
     i;j
   
     ++
   
     )

   
     14 
   
      scanf(
   
     "
   
     %d
   
     "
   
     ,
   
     &
   
     a[i][j]);

   
     15 
   
      
   
     for
   
     (i
   
     =
   
     n
   
     -
   
     1
   
     ;i
   
     >=
   
     1
   
     ;i
   
     --
   
     )

   
     16 
   
      
   
     for
   
     (j
   
     =
   
     1
   
     ;j
   
     <=
   
     i;j
   
     ++
   
     )

   
     17 
   
      a[i][j]
   
     =
   
     max(a[i
   
     +
   
     1
   
     ][j],a[i
   
     +
   
     1
   
     ][j
   
     +
   
     1
   
     ])
   
     +
   
     a[i][j];

   
     18 
   
      printf(
   
     "
   
     %d\n
   
     "
   
     ,a[
   
     1
   
     ][
   
     1
   
     ]);

   
     19 
   
      
   
     return
   
      
   
     0
   
     ;

   
     20 
   
     }

   
     21