算法题：蛇形打印矩阵

  1 // Snake.cpp : print matric(n*n)。
  2 //////////// n=3:
  3 // 1 2 6
  4 // 3 5 7
  5 // 4 8 9
  6 //////////// n=4:
  7 // 1  2  6  7
  8 // 3  5  8  13
  9 // 4  9  12 14
 10 // 10 11 15 16
 11 
 12 #include "stdafx.h"
 13 #include "vector"
 14 #include "deque"
 15 #include "algorithm"
 16 #include "iostream"
 17 #include "iomanip"
 18 
 19 using namespace std;
 20 
 21 //辅助矩阵matric
 22 //           vector
 23 //             ||
 24 //             \/
 25 //1         <--deque
 26 //2 3       <--deque
 27 //6 5 4     <--deque
 28 //7 8       <--deque
 29 //9         <--deque
 30 vector<deque<int>> matric;
 31 
 32 
 33 //初始化辅助矩阵:
 34 //1
 35 //2 3
 36 //4 5 6
 37 //7 8
 38 //9
 39 void Init(int n)
 40 {
 41     matric.clear();
 42     int row = n * 2 - 1;
 43     int col = 0;
 44     int t = 1;
 45     for (int i = 1; i <= row; ++i) {
 46         if (i <= n) col = i;
 47         else col = row - i + 1;
 48         deque<int> vec;
 49         for (int j = 1; j <= col; ++j) {
 50             vec.push_back(t);
 51             t++;
 52         }
 53         matric.push_back(vec);
 54     }
 55 
 56 }
 57 
 58 //将辅助矩阵的奇数行逆序： 
 59 //1
 60 //2 3
 61 //6 5 4
 62 //7 8
 63 //9
 64 void Adjust(int n)
 65 {
 66     int row = n * 2 - 1;
 67     for (int i = 1; i <= row; ++i) {
 68         if (i % 2 == 1) {
 69             reverse(matric.at(i-1).begin(), matric.at(i-1).end());
 70         }
 71     }
 72 }
 73 
 74 void PrintInt(const int& n)
 75 {
 76     cout << setw(3) << n;
 77 }
 78 
 79 //打印辅助矩阵for testing
 80 void PrintMatric(int n)
 81 {
 82     int row = n * 2 - 1;
 83     int col = 0;
 84 
 85     for (int i = 1; i <= row; ++i) {
 86         for_each(matric.at(i - 1).begin(), matric.at(i - 1).end(), PrintInt);
 87         cout << endl;
 88     }
 89 }
 90 
 91 // 蛇形打印
 92 // from matric:
 93 //1                          
 94 //2 3               1 2 6
 95 //6 5 4     to      3 5 7          
 96 //7 8               4 8 9         
 97 //9                          
 98 //                            
 99 //n=4:                             
100 //                            
101 //1                             
102 //2  3
103 //6  5  4               1  2  6  7  15
104 //7  8  9  10           3  5  8  14 16
105 //15 14 13 12 11   to   4  9  13 17 22
106 //16 17 18 19           10 12 18 21 23
107 //22 21 20              11 19 20 24 25
108 //23 24
109 //25
110 // 打印前n个非空的deque的首元素，并pop_front
111 void PrintSnake(int n)
112 {
113     int row = n * 2 - 1;
114     for (int i = 1; i <= row; ++i) {
115         if (matric.at(i-1).size() == 0)
116             continue;
117         for (int j = 0; j < n; ++j) {
118             cout << setw(3) << matric.at(i-1+j).front();
119             matric.at(i-1+j).pop_front();
120         }
121         cout << endl;
122     }
123 }
124 
125 int _tmain(int argc, _TCHAR* argv[])
126 {
127     int n;
128     while (true) {
129         cin >> n;
130         if (n <= 0) break;
131         Init(n);
132         cout << "init:" << endl;
133         PrintMatric(n);
134         Adjust(n);
135         cout << "adjust:" << endl;
136         PrintMatric(n);
137         cout << "snake:" << endl;
138         PrintSnake(n);
139     }
140 
141     return 0;
142 }