构造 Codeforces Round #302 (Div. 2) B Sea and Islands

 

题目传送门

 1 /*  2  题意：在n^n的海洋里是否有k块陆地  3  构造算法：按奇偶性来判断，k小于等于所有点数的一半，交叉输出L/S  4  输出完k个L后，之后全部输出S:)  5  5 10 的例子可以是这样的：  6  LSLSL  7  SLSLS  8  LSLSL  9  SLSLS 10  SSSSS 11 */ 12 #include <cstdio> 13 #include <cstring> 14 #include <algorithm> 15 #include <cmath> 16 #include <string> 17 using namespace std; 18 19 const int MAXN = 1e2 + 10; 20 const int INF = 0x3f3f3f3f; 21 22 int main(void) //Codeforces Round #302 (Div. 2) B Sea and Islands 23 { 24 freopen ("B.in", "r", stdin); 25 26 int n, k; 27 while (scanf ("%d%d", &n, &k) == 2) 28  { 29 int mx = n * n / 2; 30 if ((n*n) & 1) mx += 1; 31 if (k > mx) puts ("NO"); 32 else 33  { 34 puts ("YES"); 35 if (k == 0) 36  { 37 for (int i=1; i<=n; ++i) 38  { 39 for (int j=1; j<=n; ++j) printf ("%c", 'S'); 40 puts (""); 41  } 42  } 43 else 44  { 45 int cnt = 0; bool flag = true; 46 for (int i=1; i<=n; ++i) 47  { 48 for (int j=1; j<=n; ++j) 49  { 50 if (flag) {printf ("%c", 'L'); ++cnt;} 51 else printf ("%c", 'S'); 52 if (cnt == k) flag = false; 53 else flag = !flag; 54  } 55 if (n % 2 == 0 && cnt < k) flag = !flag; 56 puts (""); 57  } 58  } 59  } 60  } 61 62 63 return 0; 64 } 65 66 /* 67 YES 68 SSSSS 69 LLLLL 70 SSSSS 71 LLLLL 72 SSSSS 73 NO 74 */