比赛 |
2025暑期集训第7场 |
评测结果 |
AATTTTTTTT |
题目名称 |
Power Calculus |
最终得分 |
20 |
用户昵称 |
LikableP |
运行时间 |
26.304 s |
代码语言 |
C++ |
内存使用 |
3.50 MiB |
提交时间 |
2025-08-11 16:03:01 |
显示代码纯文本
// #include <algorithm>
#include <cstdio>
#include <unordered_map>
#include <vector>
using namespace std;
int n;
int ans;
unordered_map<int, bool> vis;
vector<int> use;
int k;
bool dfs(int now, int step) {
// printf("[%d %d]\n", now, step);
// if (step >= ans) return;
if (step > k) return false;
if (now < 0 || now > 2 * n) return false;
if (now == n) {
// ans = min(ans, step);
// return;
return true;
}
int siz = use.size();
// printf("item: ");
// for (auto x : use) printf("%d ", x);
// printf("\n");
// printf("[%d]", siz);
for (int i = 0; i < siz; ++i) {
int newnum = now + use[i];
if (!vis[newnum]) {
use.push_back(newnum);
vis[newnum] = 1;
if (dfs(newnum, step + 1)) return true;
vis[newnum] = 0;
use.pop_back();
}
newnum = now - use[i];
if (!vis[newnum]) {
use.push_back(newnum);
vis[newnum] = 1;
if (dfs(newnum, step + 1)) return true;
vis[newnum] = 0;
use.pop_back();
}
}
return false;
}
int main() {
freopen("pow_cal.in", "r", stdin);
freopen("pow_cal.out", "w", stdout);
while (scanf("%d", &n)) {
if (!n) break;
if (n == 1) {
printf("0\n");
continue;
}
// ans = 0x7fffffff;
for (k = 1;; ++k) {
vis.clear();
use.clear();
use.push_back(1);
if (dfs(1, 0)) {
printf("%d\n", k);
break;
}
// printf("%d\n", ans);
}
}
return 0;
}