题解报告（CDUT暑期集训——第五场）

小咪咪 2023-08-17 16:23 113阅读 0赞

# **题解报告（CDUT暑期集训——第五场）** #

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## **B - Beautiful Now** ##

### [HDU - 6351][] ###

*  **思路：直接暴力全排列就行了 最多\\(10!\\)次 题目限制2500ms 全排列大概是2000多ms（最开始数组开的20疯狂t 结束前十几秒听到尧神说把数组开小过了就马上改了一交过了（%%尧神 时间卡的太死了（** 
 *  AC代码

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#include<stdio.h> #include<iostream> #include<math.h> #include<algorithm> #include<string.h> #include<queue> #include<set> #include<string> #include<sstream> typedef long long ll; typedef unsigned long long ull; using namespace std; ll Pow_mod(ll a, ll b, ll c){ ll ans = 1; a %= c; while (b){ if (b & 1) ans = (ans * a) % c; a = (a * a) % c; b >>= 1; } return (ans % c); } int gcd(int a, int b){ return b == 0 ? a : gcd(b, a % b); } const int N = 10; const int M = 20; const int INF = 0x3f3f3f3f; int t, k, len, init_val, ans_min, ans_max, cnt, cnt_, sum; int n_[N], pos[N], vis[N]; char n[M]; void init(){ init_val = 0; len = strlen(n); for (int i = 0; i < len; i ++ ){ n_[i] = (n[i] - '0'); pos[i] = i; init_val = init_val * 10 + n_[i]; } ans_min = init_val; ans_max = init_val; } bool judge(){ memset(vis, 0, sizeof(vis)); cnt = 0; for (int i = 0; i < len; i ++ ){ if (!vis[i]){ cnt_ = 0; while (!vis[i]){ vis[i] = 1; cnt_ ++; i = pos[i]; } cnt += (cnt_ - 1); } if (cnt > k) return false; } return true; } void calc(){ while (next_permutation(pos, pos + len)){ if (n_[pos[0]] && judge()){ sum = 0; for (int i = 0; i < len; i ++ ) sum = sum * 10 + n_[pos[i]]; ans_min = min(ans_min, sum); ans_max = max(ans_max, sum); } } } int main(){ scanf("%d", &t); while (t -- ){ scanf("%s%d", n, &k); init(); calc(); printf("%d %d\n", ans_min, ans_max); } return 0; }

## **E - Everything Has Changed** ##

### [HDU - 6354][] ###

*  **思路：水题 计算几何 画图工具一画就出来了 最开始忘了判断包含的情况调过贡献了一发wa（菜是原罪**
 *  AC代码

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转载于:https://www.cnblogs.com/Misuchii/p/11276197.html

[HDU - 6351]: http://acm.hdu.edu.cn/showproblem.php?pid=6351
[HDU - 6354]: http://acm.hdu.edu.cn/showproblem.php?pid=6354