洛谷 P1934 封印

题目传送门

解题思路:

f[i]表示打到第i层的最小值

AC代码:

 #include<iostream>
 #include<cstdio>

 using namespace std;

 long long n,t,a[],sum[];
 long long f[];

 inline long long min(long long s,long long d) {
     if(s > d) return d;
     return s;
 }

 int main() {
     scanf("%d%d",&n,&t);
     for(int i = ;i <= n; i++) {
         scanf("%d",&a[i]);
         sum[i] = sum[i-] + a[i];
     }
     for(int i = ;i <= n; i++) {
         f[i] = a[i] * n * n + f[i-];
         for(int j = i - ;j >= ; j--)
             if(a[i] + a[j] <= t)
                 f[i] = min(f[i],f[j-] + (a[j] + a[i]) * (sum[i] - sum[j-]));
     }
     printf("%lld",f[n]);
     return ;
 }