Uva 11464 偶数矩阵

 1 #include <bits/stdc++.h>
 2 
 3 using namespace std;
 4 
 5 #define inf 0x3f3f3f3f
 6 
 7 int a[20][20];
 8 int b[20][20];
 9 int n;
10 
11 int dr[3] = {-1,0,0};
12 int dc[3] = {0,-1,1};
13 
14 int sum(int di,int dj) {
15     int ans = 0;
16     for(int i=0;i<3;i++)
17     {
18         int dx = di + dr[i];
19         int dy = dj + dc[i];
20 
21         if(dx>=0&&dx<n&&dy>=0&&dy<n)
22             ans +=b[dx][dy];
23     }
24     return ans;
25 }
26 
27 bool test(int i) {
28     int x = sum(n-1,i);
29     if(x%2)
30         return false;
31     else return true;
32 }
33 
34 int check(int s) {
35 
36 
37     for(int i=0;i<n;i++)
38         if(s&(1<<i)) b[0][i] = 1;
39         else b[0][i] = 0;
40 
41     for(int i=0;i<n-1;i++)
42     {
43         for(int j=0;j<n;j++) {
44             int x = sum(i,j);
45             if(x%2==0)
46                 b[i+1][j] = 0;
47             else b[i+1][j] = 1;
48         }
49     }
50 
51     for(int i=0;i<n;i++)
52         if(!test(i))
53         return inf;
54 
55     int ans = 0;
56     for(int i=0;i<n;i++) {
57         for(int j=0;j<n;j++)
58         {
59             if(a[i][j]==1&&b[i][j]==0)
60                 return inf;
61         }
62     }
63 
64     for(int i=0;i<n;i++)
65     {
66         for(int j=0;j<n;j++)
67             if(a[i][j]!=b[i][j])
68                 ans++;
69     }
70     return ans;
71 }
72 
73 int main()
74 {
75     int kase = 1,t;
76     scanf("%d",&t);
77     while(t--) {
78 
79         scanf("%d",&n);
80 
81         for(int i=0;i<n;i++)
82             for(int j=0;j<n;j++)
83                 scanf("%d",&a[i][j]);
84 
85         int ans = inf;
86         for(int s=0;s<(1<<n);s++)
87             ans = min(ans,check(s));
88 
89         printf("Case %d: ",kase++);
90         if(ans==inf)
91             printf("-1\n");
92         else printf("%d\n",ans);
93     }
94     return 0;
95 }