題意:
給定n盞燈,m個開關
下面m行給出每個開關可以控制哪些燈(即按下此開關,這些燈的狀態會改變)
下面q個詢問:一行一個詢問,一個詢問n個數字表示燈的最終狀態
問從全暗到這個狀態的方案數(一個開關只能按一次)
n條方程,等式右邊就是輸入的燈的狀態。
m個未知數,表示每個開關是否按下,系數就是這個開關能否影響到那盞燈
解完方程後首先判斷系數矩陣的秩是否和增廣矩陣的秩相同,若相同則必有解,否則則無解。
因為求的是方案數,所以求出解完方程後的自由元數量即可。
方案數=2^(自由元數量)
import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.PrintWriter; import java.math.BigInteger; import java.text.DecimalFormat; import java.util.ArrayDeque; import java.util.ArrayList; import java.util.Arrays; import java.util.Collection; import java.util.Collections; import java.util.Comparator; import java.util.Deque; import java.util.HashMap; import java.util.Iterator; import java.util.LinkedList; import java.util.Map; import java.util.PriorityQueue; import java.util.Scanner; import java.util.Stack; import java.util.StringTokenizer; import java.util.TreeMap; import java.util.TreeSet; import java.util.Queue; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; public class Main { int[][] A = new int[N][N], init = new int[N][N]; int n, m; long Gauss(int[][] mat, int row, int col){ int r, c, i, j; for(r = c = 0; r < row && c < col; r++, c++){ for(i = r; i < row; i++) if(mat[i][c]>0)break; if(i == row){r--; continue;} if(i!=r) for(j = c; j <= col; j++){ int tmp = mat[r][j]; mat[r][j] = mat[i][j]; mat[i][j] = tmp; } for(i = r+1; i < row; i++) if(mat[i][c]>0) for(j = c; j <= col; j++) mat[i][j] ^= mat[r][j]; } for(i = r; i < row; i++) if(mat[i][col]!=0)return 0L; return 1L<<(col-r); } void work() throws Exception { int T = Int(), Cas = 1; while (T-->0){ n = Int(); m = Int(); for(int i = 0; i < n; i++)for(int j = 0; j < m; j++)init[i][j] = 0; for(int i = 0, j, num; i < m; i++) { num = Int(); while(num-->0)init[Int()-1][i] = 1; } int q = Int(); out.println(Case +(Cas++)+:); while(q-->0){ for(int i = 0; i < n; i++)for(int j = 0; j < m; j++)A[i][j] = init[i][j]; for(int i = 0; i < n; i++)A[i][m] = Int(); out.println(Gauss(A, n, m)); } } } public static void main(String[] args) throws Exception { Main wo = new Main(); in = new BufferedReader(new InputStreamReader(System.in)); out = new PrintWriter(System.out); // in = new BufferedReader(new InputStreamReader(new FileInputStream(new File(input.txt)))); // out = new PrintWriter(new File(output.txt)); wo.work(); out.close(); } static int N = 56; static int M = N * 2; DecimalFormat df = new DecimalFormat(0.0000); static int inf = (int) 1e9; static long inf64 = (long) 1e18; static double eps = 1e-8; static double Pi = Math.PI; static int mod = (int) 1e9 + 7; private String Next() throws Exception { while (str == null || !str.hasMoreElements()) str = new StringTokenizer(in.readLine()); return str.nextToken(); } private int Int() throws Exception { return Integer.parseInt(Next()); } private long Long() throws Exception { return Long.parseLong(Next()); } private double Double() throws Exception { return Double.parseDouble(Next()); } StringTokenizer str; static Scanner cin = new Scanner(System.in); static BufferedReader in; static PrintWriter out; class Edge{ int from, to, dis, nex; Edge(){} Edge(int from, int to, int dis, int nex) { this.from = from; this.to = to; this.dis = dis; this.nex = nex; } } Edge[] edge = new Edge[M<<1]; int[] head = new int[N]; int edgenum; void init_edge(){ for(int i = 0; i < N; i++)head[i] = -1; edgenum = 0;} void add(int u, int v, int dis){ edge[edgenum] = new Edge(u, v, dis, head[u]); head[u] = edgenum++; } /* */ int upper_bound(int[] A, int l, int r, int val) {// upper_bound(A+l,A+r,val)-A; int pos = r; r--; while (l <= r) { int mid = (l + r) >> 1; if (A[mid] <= val) { l = mid + 1; } else { pos = mid; r = mid - 1; } } return pos; } int lower_bound(int[] A, int l, int r, int val) {// upper_bound(A+l,A+r,val)-A; int pos = r; r--; while (l <= r) { int mid = (l + r) >> 1; if (A[mid] < val) { l = mid + 1; } else { pos = mid; r = mid - 1; } } return pos; } int Pow(int x, int y) { int ans = 1; while (y > 0) { if ((y & 1) > 0) ans *= x; y >>= 1; x = x * x; } return ans; } double Pow(double x, int y) { double ans = 1; while (y > 0) { if ((y & 1) > 0) ans *= x; y >>= 1; x = x * x; } return ans; } int Pow_Mod(int x, int y, int mod) { int ans = 1; while (y > 0) { if ((y & 1) > 0) ans *= x; ans %= mod; y >>= 1; x = x * x; x %= mod; } return ans; } long Pow(long x, long y) { long ans = 1; while (y > 0) { if ((y & 1) > 0) ans *= x; y >>= 1; x = x * x; } return ans; } long Pow_Mod(long x, long y, long mod) { long ans = 1; while (y > 0) { if ((y & 1) > 0) ans *= x; ans %= mod; y >>= 1; x = x * x; x %= mod; } return ans; } int gcd(int x, int y) { if (x > y) { int tmp = x; x = y; y = tmp; } while (x > 0) { y %= x; int tmp = x; x = y; y = tmp; } return y; } int max(int x, int y) { return x > y ? x : y; } int min(int x, int y) { return x < y ? x : y; } double max(double x, double y) { return x > y ? x : y; } double min(double x, double y) { return x < y ? x : y; } long max(long x, long y) { return x > y ? x : y; } long min(long x, long y) { return x < y ? x : y; } int abs(int x) { return x > 0 ? x : -x; } double abs(double x) { return x > 0 ? x : -x; } long abs(long x) { return x > 0 ? x : -x; } boolean zero(double x) { return abs(x) < eps; } double sin(double x) { return Math.sin(x); } double cos(double x) { return Math.cos(x); } double tan(double x) { return Math.tan(x); } double sqrt(double x) { return Math.sqrt(x); } double fabs(double x){return x>0?x:-x;} }
因為求的是方案數,所以求出解完方程後的自由元數量即可。