BZOJ1393 [Ceoi2008]knights

  1 /**************************************************************
  2     Problem: 1393
  3     User: rausen
  4     Language: C++
  5     Result: Accepted
  6     Time:992 ms
  7     Memory:2372 kb
  8 ****************************************************************/
  9  
 10 #include <cstdio>
 11 #include <algorithm>
 12  
 13 using namespace std;
 14 const int dx[] = {-2, -2, -1, 1};
 15 const int dy[] = {1, -1, -2, -2};
 16 const int N = 2e5 + 5;
 17 const int inf = 1e8;
 18  
 19 int n, k;
 20 int Ans, ansx[N], ansy[N];
 21  
 22 inline int read();
 23 inline void print (const int &);
 24  
 25 inline bool calc_sg(int x, int y) {
 26     if ((x % 4 == 1 || x % 4 == 2) && (y % 4 == 1 || y % 4 == 2)) return 0;
 27     if (n % 4 == 1 && ((x == n && y != n - 1) || (y == n && x != n - 1))) return 0;
 28     if (n % 4 == 0 && x == n && y == n) return 0;
 29     return 1;
 30 }
 31  
 32 inline bool in(const int &x, const int &y) {
 33     return (x > 0 && y > 0 && x <= n && y <= n);
 34 }
 35  
 36 #define X x + dx[k]
 37 #define Y y + dy[k]
 38 inline int find_lose(int x, int y) {
 39     if (x == n || y == n) return 2 * ((int) (x + y - 2) / 4);
 40     return 2 * ((int) (x + y - 1) / 4);
 41 }
 42  
 43 inline int find_win(int x, int y) {
 44     int k, res = 0;
 45     for (k = 0; k < 4; ++k)
 46         if (in(X, Y) && calc_sg(X, Y) == 0)
 47             res = max(res, find_lose(X, Y));
 48     return res + 1;
 49 }
 50  
 51 inline int calc_lose(int x, int y, int i) {
 52     int k, tmp = inf;
 53     for (k = 0; k < 4; ++k) 
 54         if (in(X, Y) && calc_sg(X, Y) == 1 && find_win(X, Y) < tmp) {
 55             tmp = find_win(X, Y);
 56             ansx[i] = X, ansy[i] = Y;
 57         }
 58 }
 59  
 60 inline int calc_win(int x, int y, int i) {
 61     int k, tmp = -1;
 62     for (k = 0; k < 4; ++k)
 63         if (in(X, Y) && calc_sg(X, Y) == 0 && tmp < find_lose(X, Y)) {
 64             tmp = find_lose(X, Y);
 65             ansx[i] = X, ansy[i] = Y;
 66         }
 67 }
 68 #undef X
 69 #undef Y
 70  
 71 int main() {
 72     int i, x, y, tmp, max_lose = 0, max_win = 0;
 73     k = read(), n = read();
 74     for (i = 1; i <= k; ++i) {
 75         x = read(), y = read();
 76         tmp = calc_sg(x, y);
 77         if (tmp == 0) {
 78             max_lose = max(max_lose, find_lose(x, y));
 79             calc_lose(x, y, i);
 80             continue;
 81         }
 82         max_win = max(max_win, find_win(x, y));
 83         calc_win(x, y, i);
 84     }
 85     if (max_lose > max_win) puts("NO"); else {
 86         puts("YES");
 87         for (i = 1; i <= k; ++i) {
 88             print(ansx[i]), putchar(‘ ‘);
 89             print(ansy[i]), putchar(‘\n‘);
 90         }
 91     }
 92     return 0;
 93 }
 94  
 95 inline int read() {
 96     int x = 0;
 97     char ch = getchar();
 98     while (ch < ‘0‘ || ‘9‘ < ch)
 99         ch = getchar();
100     while (‘0‘ <= ch && ch <= ‘9‘) {
101         x = x * 10 + ch - ‘0‘;
102         ch = getchar();
103     }
104     return x;
105 }
106  
107 inline void print(const int &x) {
108     static int tot, pr[20], t;
109     t = x, tot = 0;
110     while (t)   
111         pr[++tot] = t % 10, t /= 10;
112     if (!tot) putchar(‘0‘);
113     while(tot)
114         putchar(‘0‘ + pr[tot--]);
115 }