Jinan Study Day 5 T3 AM

"Title description"

Rly can't play chess now, as many people don't know. However, as a oier,rly of course did eight Queen questions. Here again a few more words, the Queen can attack the same row with the same diagonal line, in

N*n's chessboard, placing n queens so that they can not attack each other, to find the number of different solutions, this is the classic n queen problem. Now the problem of promoting the N queen question, this question for you

It's a piece of cake. But because the last time rly to break the chessboard, and do not have a new, so rly plan a little bit, the problem is in the broken board of the N queen problem. He wants to know ... (You know that.) ）

Wives are the same.

"Input description"

A row, an integer n.

The next n rows, n integers per line, or 0, mean no bad, or 1, means bad.

"Output description"

A row that outputs a different number of connectors.

"Sample Input"

4

1 0 1 1

1 1 1 0

0 1 1 1

1 1 0 1

"Sample Output"

1

"Data Range"

For 40% of data, n<=13.

For 100% of data, n<=16.

For 30% of the data the chessboard is not broken, you can think Rly again to buy a new one.

1 /*bit operation optimization n Queens*/2#include <cstdio>3#include <iostream>4 #defineN 205 using namespacestd;6 intHang[n],n,ans;7 voidDfsintTintAintBintC//a,b,c are binary numbers, indicating which column or diagonal is missing the Queen, 1 for the8 {9     if(t==n+1)Ten     { Oneans++;return; A     } -     intS= ((1<<n)-1) & (hang[t]|a|b|c)); -     /* the S is a binary number that represents the current column in which to put the Queen - (HANG[T]|A|B|C) indicates which columns are left out of the column and diagonal angles - Plus ~ (inverse), which columns can be placed Queen -     */  +      while(S) -     { +         intx=s& (-s);//x indicates where the queen can be placed now. ADFS (t+1, A+x, (b+x) <<1, (c+x) >>1); ats-=x; -     } - } - intMain () - { -scanf"%d",&n); in      for(intI=1; i<=n;i++) -        for(intj=1; j<=n;j++) to       { +           intX;SCANF ("%d",&x); -hang[i]+=x<< (J-1); the       } *Dfs1,0,0,0); $printf"%d", ans);Panax Notoginseng     return 0; -}

Idea: The N queen problem after the optimization of bit arithmetic

Jinan Study Day 5 T3 AM