HDU4850 Wow! Such String! —— 字符串构造
题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=4850
代码如下：
1 #include <iostream> 2 #include <cstdio> 3 #include <cstring> 4 #include <cstdlib> 5 #include <string> 6 #include <vector> 7 #include <map> 8 #include <set> 9 #include <queue> 10 #include <sstream> 11 #include <algorithm> 12 using namespace std; 13 #define pb push_back 14 #define mp make_pair 15 #define ms(a, b) memset((a), (b), sizeof(a)) 16 #define eps 0.0000001 17 typedef long long LL; 18 const int INF = 2e9; 19 const LL LNF = 9e18; 20 const int mod = 1e9+7; 21 const int maxn = 26*26*26*26; 22 int a[maxn+10]; 23 int vis[26][26][26][26]; 24 25 26 void solve() 27 { 28 a[0] = a[1] = a[2] = 0; 29 for(int i = 3; i<maxn+3; i++) 30 { 31 for(int j = 25; j>=0; j--) 32 { 33 if(vis[a[i-3]][a[i-2]][a[i-1]][j]==0) 34 { 35 vis[a[i-3]][a[i-2]][a[i-1]][j] = 1; 36 a[i] = j; 37 break; 38 } 39 } 40 } 41 } 42 43 int main() 44 { 45 int n; 46 solve(); 47 while(scanf("%d",&n)!=EOF) 48 { 49 if(n>maxn+3) 50 printf("Impossible"); 51 else 52 for(int i = 0; i<n; i++) 53 printf("%c",a[i]+'a'); 54 putchar('\n'); 55 } 56 }
