需剪枝：
```cpp
#include<bits/stdc++.h>
using namespace std;
int n, m;
const int manx = 1e6;
int ans = 987654321;
int mins[manx],minv[manx];
inline void dfs(int c,int v, int s,int h,int r) {
if(c == 0){
if(v == n) ans = min(ans ,s);
return;
}
if(v + minv[c] > n) return;
if(s + mins[c] > ans) return;
if(s + 2 *(n-v) / r > ans ) return;
for (int i = r - 1; i >= c; --i)
{
if(c == m) s = i * i;
int Maxh = min(h - 1,(n - v - minv[c - 1])/(i * i));
for (int j = Maxh; j >= c; --j)
dfs(c - 1, v + i * i * j, s + 2 * i * j,j,i);
}}
int main() {
scanf("%d%d", &n, &m);
int MaxR = sqrt(n);
for(int i = 1;i <= n; i++){
minv[i] = minv[i-1] + i * i * i;
mins[i] = mins[i-1] + 2 * i * i;
}
dfs(m,0,0,n,MaxR);
if(ans == 987654321)
cout<<0<<endl;
else cout<<ans<<endl;
return 0;
}
by dream_dad @ 2024-08-30 19:16:24
@[Vlang](/user/1054383)
by dream_dad @ 2024-08-30 19:16:38
没剪枝，包TLE的
by ZhouZhaoYuan0620 @ 2024-09-22 15:36:57