题目链接：http://hihocoder.com/problemset/problem/1196
1 #include <bits/stdc++.h> 2 using namespace std; 3 4 typedef pair<int, int> pii; 5 const int maxn = 230; 6 int equ, var; 7 int a[maxn][maxn]; 8 int x[maxn]; 9 int free_x[maxn]; 10 int free_num; 11 int ret; 12 13 int gauss() { 14 int max_r, col, k; 15 free_num = 0; 16 for(k = 0, col = 0; k < equ && col < var; k++, col++) { 17 max_r = k; 18 for(int i = k + 1; i < equ; i++) { 19 if(abs(a[i][col]) > abs(a[max_r][col])) 20 max_r = i; 21 } 22 if(a[max_r][col] == 0) { 23 k--; 24 free_x[free_num++] = col; 25 continue; 26 } 27 if(max_r != k) { 28 for(int j = col; j < var + 1; j++) 29 swap(a[k][j], a[max_r][j]); 30 } 31 for(int i = k + 1; i < equ; i++) { 32 if(a[i][col] != 0) { 33 for(int j = col; j < var + 1; j++) { 34 a[i][j] ^= a[k][j]; 35 } 36 } 37 } 38 } 39 for(int i = k; i < equ; i++) { 40 if(a[i][col] != 0) 41 return -1; 42 } 43 if(k < var) return var - k; 44 for(int i = var - 1; i >= 0; i--) { 45 x[i] = a[i][var]; 46 for(int j = i + 1; j < var; j++) { 47 x[i] ^= (a[i][j] & x[j]); 48 } 49 } 50 return 0; 51 } 52 53 char G[maxn][maxn]; 54 int n, m; 55 56 int main() { 57 // freopen("in", "r", stdin); 58 m = 5, n = 6; 59 var = equ = 30; 60 ret = 0; 61 memset(a, 0, sizeof(a)); 62 for(int i = 0; i < n; i++) scanf("%s", G[i]); 63 for(int i = 0; i < m; i++) { 64 for(int j = 0; j < n; j++) { 65 if(G[i][j] == '0') a[i*n+j][var] = 1; 66 else a[i*n+j][var] = 0; 67 } 68 } 69 for(int i = 0; i < 30; i++) { 70 a[i][i] = 1; 71 if(i % 6 != 0) a[i-1][i] = 1; 72 if(i % 6 != 5) a[i+1][i] = 1; 73 if(i > 5) a[i-6][i] = 1; 74 if(i < 24) a[i+6][i] = 1; 75 } 76 int v = gauss(); 77 if(v == -1) ret = -1; 78 else if(v != 0) { 79 ret = maxn; 80 int tot = 1 << v; 81 for(int i = 0; i < tot; i++) { 82 int cnt = 0; 83 for(int j = 0; j < v; j++) { 84 if(i&(1<<j)) { 85 x[free_x[j]] = 1; 86 cnt++; 87 } 88 else x[free_x[j]] = 0; 89 } 90 for(int j = var - v - 1; j >= 0; j--) { 91 int idx; 92 for(idx = j; idx < var; idx++) { 93 if(a[j][idx]) break; 94 } 95 x[idx] = a[j][var]; 96 for(int l = idx + 1; l < var; l++) { 97 if(a[j][l]) x[idx] ^= x[l]; 98 } 99 cnt += x[idx]; 100 } 101 ret = min(ret, cnt); 102 } 103 } 104 else for(int i = 0; i < var; i++) ret += x[i]; 105 printf("%d ", ret); 106 vector<pii> va; 107 for(int i = 0; i < 30; i++) { 108 if(x[i]) { 109 int pos = i + 1; 110 int r = 1, c = 0; 111 while(pos > 6) { 112 pos -= 6; 113 r++; 114 } 115 c += pos; 116 va.push_back(pii(r, c)); 117 } 118 } 119 sort(va.begin(), va.end()); 120 for(int i = 0; i < va.size(); i++) { 121 printf("%d %d ", va[i].first, va[i].second); 122 } 123 return 0; 124 }