二维数组中的查找

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/* * 在一个二维数组中，每一行都是按照从左到右 * 递增的顺序排序，每一列都是按照从上到下递增 * 的顺序排序。请完成一个函数，输入这样的一个 二位数组和一个整数，判断数组中是否含有该整数。 */   /* * 解法1：暴力搜索法，时间复杂度为O(n^2) */   #include<iostream>   using namespace std;   bool search_num(const int* nums, int rows, int cols, const int& num) {     if (nums != nullptr && rows > 0 && cols > 0)     {         for (int i = 0; i < rows; i++)         {             for (int j = 0; j < cols; j++)             {                 if (nums[i * cols + j] == num)                 {                     return true;                 }             }         }     }       return false; }   int main() {     const int rows = 4;     const int cols = 4;     const int lens = rows * cols;     int* nums = new int[lens]();     for (int i = 0; i < lens; ++i)     {         nums[i] = i + 1;     }       int num;           //要查找的数字     cin >> num;       bool result = search_num(nums, rows, cols, num);       if (result)     {         cout << "the matrix has this number." << endl;     }     else     {         cout << "the matrix do not has this number." << endl;     }       delete[] nums;     nums = nullptr;   }   /* *解法2：利用搜索数组的特性，首先选取数组中右上角的数字。如果该数字等于要查找的数字，则 * 查找结束；如果该数字大于要查找的数字，则剔除这个数字所在的列；如果这个数字小于要查找 的数字，则剔除这个数字所在的行。这样就可以一步一步的缩小范围了。* */   #include<iostream>   using namespace std;   bool Find(const int* matrix, int rows, int cols, const int& num) {     if (matrix != nullptr && rows > 0 && cols > 0)     {         int row = 0;         int col = cols - 1;         while (row < rows && col >= 0)         {             if (matrix[row * cols + col] == num)             {                 return true;             }             else if (matrix[row * cols + col] > num)             {                 col--;             }             else             {                 row++;             }         }     }       return false; }   int main() {     const int rows = 4;     const int cols = 4;     const int lens = rows * cols;     int* nums = new int[lens]();     for (int i = 0; i < lens; ++i)     {         nums[i] = i + 1;     }       int num;           //要查找的数字     cin >> num;       bool result = Find(nums, rows, cols, num);       if (result)     {         cout << "the matrix has this number." << endl;     }     else     {         cout << "the matrix do not has this number." << endl;     }     delete[] nums;     nums = nullptr;   }