P1216-[IOI1994][USACO1.5]数字三角形 Number Triangles 

 1 #include <bits/stdc++.h>
 2 #define _for(i,a,b) for(int i = (a);i < b;i ++)
 3 typedef long long ll;
 4 using namespace std;
 5 int rnt = 0;
 6 int N;
 7 inline ll read()
 8 {
 9     ll ans = 0;
10     char ch = getchar(), last = ' ';
11     while(!isdigit(ch)) last = ch, ch = getchar();
12     while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar();
13     if(last == '-') ans = -ans;
14     return ans;
15 }
16 inline void write(ll x)
17 {
18     if(x < 0) x = -x, putchar('-');
19     if(x >= 10) write(x / 10);
20     putchar(x % 10 + '0');
21 }
22 
23 int main()
24 {
25     N = read();
26     int dp[2][N];
27     memset(dp,0,sizeof(dp));
28     dp[0][0] = read();
29     int rnt = 0;
30     _for(i,1,N)
31     {
32         _for(j,0,i+1)
33         {
34             int tmp = read();
35             if(j==0)
36                 dp[i&0x1][j] = dp[!(i&0x1)][j] + tmp;
37             else if(j==i)
38                 dp[i&0x1][j] = dp[!(i&0x1)][j-1] + tmp;
39             else
40                 dp[i&0x1][j] = tmp + max(dp[!(i&0x1)][j],dp[!(i&0x1)][j-1]);
41         }
42     }
43     
44     _for(i,0,N)
45         rnt = max(rnt,dp[!(N&0x1)][i]);
46     write(rnt);
47     return 0;
48 }

 

posted @ 2019-08-01 16:28  Asurudo  阅读(146)  评论(0)    收藏  举报