#include <cstdio>#include <algorithm>#include <cmath>using namespace std;#define MAX_LAYER_NUM 25#define INF 0x3f3f3f3fint layer_num;int total_volume;int min_vol[MAX_LAYER_NUM];int min_area[MAX_LAYER_NUM];int ans;void init(){ min_area[0] = min_vol[0] = 0; for (int i = 1; i <= 20; i++) { min_vol[i] = min_vol[i - 1] + i * i * i; min_area[i] = min_area[i - 1] + 2 * i * i; }}void DFS(int r_limit, int h_limit, int layer, int area, int volume){ if (layer == 0) { if (volume != total_volume) return; ans = min(ans, area); return; } if (total_volume - volume < min_vol[layer]) return; if (ans - area < min_area[layer]) return; if (layer < layer_num && area + 2 * (total_volume - volume) / r_limit > ans) return; for (int i = r_limit; i >= layer; i--) { if (layer == layer_num) { area = i * i; } int max_h = (total_volume - min_vol[layer - 1] - volume) / (i * i); for (int j = min(max_h, h_limit); j >= layer; j--) { DFS(i - 1, j - 1, layer - 1, area + 2 * i * j, volume + i * i * j); } }}int main(){ scanf("%d%d", &total_volume, &layer_num); ans = INF; init(); DFS((int)sqrt(total_volume), total_volume, layer_num, 0, 0); printf("%dn", ans); return 0;}
