Bzoj 1087: [SCOI2005] Non-invasive king (pressure DP)

Simple-like pressure dp ...

The DP (x, H, s) represents the current X line, uses H king, and the current row has a state of S.

Consider transfer: DP (x, h, s) =∑dp (X-1, h-cnt_1 (s), S ') (s and S ' two rows do not conflict, cnt_1 (s) indicates how many King s states are used)

I have all sorts of preprocessing, so code's equation is a little different.

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#include <cstdio>

#include <cstdlib>#include <cstring>#include <algorithm>#include <vector>#include <iostream>#define CLR (x, C) memset (x, C, sizeof (x))#define REP (i, n) for (int i = 0; i < n; ++i)#define B (i) (1 << (i))using namespace std;typedef long Long ll;const int MAXN = ten;const int maxstate = +;vector< int > state;vector< int > cnt;vector< int > ok[maxstate];int n, K;ll d[MAXN] [MAXN * MAXN] [maxstate];void init () {state.clear (), Cnt.clear ();CLR (d,-1);CLR (d[0], 0);cin >> n >> K;Rep (s, b (n)) if (! (S & (S << 1))) {State.push_back (s);int t = 0;for (int h = s; h; h >>= 1) T + = h & 1;Cnt.push_back (t);d[0 [t] [State.size ()-1] = 1;}Rep (i, State.size ())ok[i].clear ();Rep (i, State.size ())For (int j = i; J < State.size (); j + +)if (! (state[j] & state[i]) &&! ((state[j] << 1) & state[i]) &&! ((state[i] << 1) & state[J])) {ok[I].push_back (j);if (i! = j) ok[J].push_back (i);    }}ll DP (int x, int h, int t) {if (H < 0) return 0;ll &ans = d[x [h] [t];if (ans! =-1) return ans;ans = 0;if (H < cnt[T]) return ans;For (vector< int >:: iterator it = ok[T].begin (); it! = ok[T].end (); it++)ans + = DP (x-1, h-cnt[T], *it);return ans;}void Work () {ll ans = 0;Rep (i, State.size ())ans + = DP (n-1, k, i);cout << ans << "\ n";}int main () {//freopen ("test.in", "R", stdin);//freopen ("Test.out", "w", stdout);init ();Work ();return 0;} 

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1087: [SCOI2005] Non-aggression king Time Limit:Ten Sec Memory Limit:162 MB
Submit:1974 Solved:1171
[Submit] [Status] [Discuss] Description

Put K Kings in NxN's chessboard, so that they do not attack each other, there are many kinds of layout plan. The king can attack it up and down, as well as the left upper left lower right up to the bottom right in the next eight directions in the vicinity of a grid, a total of 8 squares.

Input

Only one row, containing two numbers n,k (1 <=n <=9, 0 <= K <= n * N)

Output

Number of scenarios.

Sample Input 3 2Sample Output -HINT

Source

Bzoj 1087: [SCOI2005] Non-invasive king (pressure DP)