Description Katu Puzzle is presented as a directed graph G(V, E) with each edge e(a, b) labeled by a boolean operator op (one of AND, OR, XOR) and an integer c (0 ≤ c ≤ 1). One Katu is solvable if one can find each vertex Vi a value Xi (0 ≤ Xi ≤ 1) s…

题目链接:http://poj.org/problem?id=3678 题目: 题意:给你a,b,c,op,op为逻辑运算符或.与.异或,使得a op b = c,让你判断这些运算符是否存在矛盾,不存在输出YES,存在输出NO. 思路:2-SAT问题.2-SAT问题一般都是每个节点有两种选择,并且在节点中间将存在一定的限制,譬如a为1,那么b必须为1或a为0,b必须为1……而且当一个命题存在时,它的逆否命题必然存在(此处由命题为真,则其逆否命题也为真得证).我们通过将这些关系转换成有向的边,通过…

Katu Puzzle Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 6714   Accepted: 2472 Description Katu Puzzle is presented as a directed graph G(V, E) with each edge e(a, b) labeled by a boolean operator op (one of AND, OR, XOR) and an integ…

题目 Katu Puzzle is presented as a directed graph G(V, E) with each edge e(a, b) labeled by a boolean operator op (one of AND, OR, XOR) and an integer c (0 ≤ c ≤ 1). One Katu is solvable if one can find each vertex Vi a value Xi (0 ≤ Xi ≤ 1) such that…

http://poj.org/problem?id=3678 总觉得这题比例题简单. 设a为x取0的点,a+n为x取1的点. 我们还是定义a到b表示取a必须取b. 那么我们有: 当AND: 1.当c=1:add(a,a+n); add(b,b+n);//我们不能取0的点,所以我们让程序一旦取0必会矛盾,下面类似的同理. 2.当c=0:add(a+n,b); add(b+n,a); 当OR 1.当c=1:add(a,b+n);add(b,a+n); 2.当c=0:add(a+n,a);add(b+…

Description Katu Puzzle ≤ c ≤ ). One Katu ≤ Xi ≤ ) such that for each edge e(a, b) labeled by op and c, the following formula holds: Xa op Xb = c The calculating rules are: AND 0 1 0 0 0 1 0 1 OR 0 1 0 0 1 1 1 1 XOR 0 1 0 0 1 1 1 0 Given a Katu Puzzl…

                                                                     Katu Puzzle Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 11429   Accepted: 4233 Description Katu Puzzle is presented as a directed graph G(V, E) with each edge e(a, …

Katu Puzzle Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 6553   Accepted: 2401 Description Katu Puzzle is presented as a directed graph G(V, E) with each edge e(a, b) labeled by a boolean operator op (one of AND, OR, XOR) and an integ…

Description Katu Puzzle is presented as a directed graph G(V, E) with each edge e(a, b) labeled by a boolean operator op (one of AND, OR, XOR) and an integer c (0 ≤ c ≤ 1). One Katu is solvable if one can find each vertex Vi a value Xi (0 ≤ Xi ≤ 1) s…

Description 给出一个关系,包括 And,Xor,Or 问是否存在解. Sol 经典的2-SAT问题. 把每个值看成两个点,一个点代表选 \(0\) ,另一个代表选 \(1\) . 首先来看 Xor : 如果两个值异或起来为 \(1\) :那么连边 \((i_0,j_1),(i_1,j_0),(j_0,i_1),(j_1,i_0)\) . 否则 连边 \((i_0,j_0),(i_1,j_1),(j_0,i_0),(j_1,i_1)\) . 然后是 And. 如果两个值 And 起来为…