洛谷 P1464 Function（简单记忆化）

嗯...

让一切从水开始吧...

水过初赛，但愿复赛能够接着水过...

这道题不记忆化会tle，所以用空间换时间，将每次的答案（只有20*20*20个）存下来，如果之前已经求过，就不需要重复求了....

AC代码：

 #include<cstdio>
 #include<cstring>
 #include<iostream>

 using namespace std;

 long long ans[][][];

 inline long long w(long long a, long long b, long long c){
     if(a <=  || b <=  || c <= ) return ;
     else if(ans[a][b][c]) return ans[a][b][c];
     else if(a >  || b >  || c > ) ans[a][b][c] = w(, , );
     else if(a < b && b < c)  ans[a][b][c] = w(a, b, c - ) + w(a, b - , c - ) - w(a, b - , c);
     else ans[a][b][c] = w(a - , b, c) + w(a - , b - , c) + w(a - , b, c - ) - w(a - , b - , c - );
     return ans[a][b][c];
 }

 int main(){
     long long a, b, c;
     while(~scanf("%lld%lld%lld", &a, &b, &c)){
         memset(ans, , sizeof(ans));
         if(a == - && b == - && c == -) break;
         printf("w(%lld, %lld, %lld) = ", a, b, c);
         if(a > ) a = ;
         if(b > ) b = ;
         if(c > ) c = ;
         printf("%lld\n", w(a, b, c));
     }
     return ;
 }

AC代码