螺旋矩阵

#include<stack>
#include<algorithm>
#include<vector>
#include<queue>
#include<iostream>
#include<iterator>
#include<functional>
#include<list>

using namespace std;

const int M = 5;
const int N = 6;

vector<vector<int> > build_spiral_matrix(int m, int n);
vector<int> print_spiral_matrix(const vector<vector<int> > &vec);

int main() {
auto mat1=build_spiral_matrix(M, N);
for (int j = 0;j < M;++j) {
copy(mat1[j].begin(), mat1[j].end(), ostream_iterator<int>(cout, " "));
cout << endl;
}
auto ans2 = print_spiral_matrix(mat1);
copy(ans2.begin(), ans2.end(), ostream_iterator<int>(cout, " "));
return 0;
}

//螺旋矩阵的构造
vector<vector<int> > build_spiral_matrix(int m, int n) {
vector<vector<int>> ans(m, vector<int>(n, 0));
int index = 0;
int i;
int bx = 0;
int ex = n - 1;
int by = 0;
int ey = m - 1;
while (1) {
for (i = bx;i <= ex;++i) { ans[by][i] = ++index; }
if (++by>ey) break;
for (i = by;i <= ey;++i) { ans[i][ex] = ++index; }
if (--ex<bx) break;
for (i = ex;i >= bx;--i) { ans[ey][i] = ++index; }
if (--ey<by) break;
for (i = ey;i >= by;--i) { ans[i][bx] = ++index; }
if (++bx>ex) break;
}
return ans;
}

//螺旋矩阵的打印
vector<int> print_spiral_matrix(const vector<vector<int> > &vec) {
vector<int> ans;
if (vec.size() == 0) { return ans; }
int bx = 0;
int ex = vec[0].size() - 1;
int by = 0;
int ey = vec.size() - 1;
int i;
while (1) {
for (i = bx;i <= ex;++i) { ans.push_back(vec[by][i]); }
if (++by>ey) break;
for (i = by;i <= ey;++i) { ans.push_back(vec[i][ex]); }
if (--ex<bx) break;
for (i = ex;i >= bx;--i) { ans.push_back(vec[ey][i]); }
if (--ey<by) break;
for (i = ey;i >= by;--i) { ans.push_back(vec[i][bx]); }
if (++bx>ex) break;
}
return ans;
}