在矩阵中查找唯一元素 · GeeksForGeeks 中文系列教程

# 在矩阵中查找唯一元素 > 原文： [https://www.geeksforgeeks.org/find-unique-elements-matrix/](https://www.geeksforgeeks.org/find-unique-elements-matrix/) 给定具有 n 行和 m 列的矩阵 mat [] []。我们需要在矩阵中找到唯一元素，即矩阵中未重复的元素或频率为 1 的元素。 **示例**： ``` Input : 20 15 30 2 2 3 5 30 6 7 6 8 Output : 3 20 5 7 8 15 Input : 1 2 3 5 6 2 1 3 5 6 2 2 Output : No unique element in the matrix ``` 请按照以下步骤查找唯一元素： 1.创建一个空的哈希表或字典。 2.遍历矩阵的所有元素 3.如果字典中存在元素，则增加其计数 4.否则插入值为= 1 的元素。 ## C++ ```cpp // C++ program to find unique // element in matrix #include<bits/stdc++.h> using namespace std; #define R 4 #define C 4 // function that calculate unique element int unique(int mat[R][C], int n, int m) { int maximum = 0, flag = 0; for(int i = 0; i < n; i++) for(int j = 0; j < m; j++) // Find maximum element in // a matrix if(maximum < mat[i][j]) maximum = mat[i][j]; // Take 1-D array of (maximum + 1) // size int b[maximum + 1] = {0}; for(int i = 0 ; i < n; i++) for(int j = 0; j < m; j++) b[mat[i][j]]++; //print unique element for(int i = 1; i <= maximum; i++) if(b[i] == 1) cout << i << " "; flag = 1; if(!flag){ cout << "No unique element in the matrix"; } } // Driver program int main() { int mat[R][C] = {{ 1, 2, 3, 20}, {5, 6, 20, 25}, {1, 3, 5, 6}, {6, 7, 8, 15}}; // function that calculate unique element unique(mat, R, C); return 0; } // This code is contributed by Naman_Garg. ``` ## Java ```java // Java program to find unique // element in matrix class GFG { static int R = 4, C = 4; // function that calculate // unique element static void unique(int mat[][], int n, int m) { int maximum = 0, flag = 0; for(int i = 0; i < n; i++) for(int j = 0; j < m; j++) // Find maximum element // in a matrix if(maximum < mat[i][j]) maximum = mat[i][j]; // Take 1-D array of // (maximum + 1) size int b[] = new int [maximum + 1]; for(int i = 0 ; i < n; i++) for(int j = 0; j < m; j++) b[mat[i][j]]++; //print unique element for(int i = 1; i <= maximum; i++) if(b[i] == 1) System.out.print(i + " "); flag = 1; if(flag == 0) { System.out.println("No unique element " + "in the matrix"); } } // Driver Code public static void main(String args[]) { int mat[][] = {{1, 2, 3, 20}, {5, 6, 20, 25}, {1, 3, 5, 6}, {6, 7, 8, 15}}; // function that calculate // unique element unique(mat, R, C); } } // This code is contributed // by Arnab Kundu ``` ## Python3 ```py # Python 3 program to find unique # element in matrix def unique(mat, n, m): maximum = 0; flag = 0 for i in range(0, n): for j in range(0, m): # Find maximum element in # a matrix if(maximum < mat[i][j]): maximum = mat[i][j]; uniqueElementDict = [0] * (maximum + 1) # loops to traverse through the matrix for i in range(0, n): for j in range(0, m): uniqueElementDict[mat[i][j]] += 1 # Print all those keys whose count is 1 for key in range(maximum + 1): if uniqueElementDict[key] == 1: print (key, end = " ") flag = 1 if(flag == 0): print("No unique element in the matrix") # Driver Code mat = [[1, 2, 3, 20], [5, 6, 20, 25], [1, 3, 5, 6], [6, 7, 8, 15]] n = 4 m = 4 unique(mat, n, m) ``` ## C# ```cs // C# program to find unique // element in matrix using System; class GFG { static int R = 4, C = 4; // function that calculate // unique element static void unique(int [,]mat, int n, int m) { int maximum = 0, flag = 0; for(int i = 0; i < n; i++) for(int j = 0; j < m; j++) // Find maximum element // in a matrix if(maximum < mat[i, j]) maximum = mat[i, j]; // Take 1-D array of // (maximum + 1) size int []b = new int [maximum + 1]; for(int i = 0 ; i < n; i++) for(int j = 0; j < m; j++) b[mat[i, j]]++; // print unique element for(int i = 1; i <= maximum; i++) if(b[i] == 1) Console.Write(i + " "); flag = 1; if(flag == 0) { Console.WriteLine("No unique element " + "in the matrix"); } } // Driver Code public static void Main() { int [,]mat = {{1, 2, 3, 20}, {5, 6, 20, 25}, {1, 3, 5, 6}, {6, 7, 8, 15}}; // function that calculate // unique element unique(mat, R, C); } } // This code is contributed // by Subhadeep ``` ## PHP ```php <?php // PHP program to find unique // element in matrix $R = 4; $C = 4; // function that calculate unique element function unique($mat, $n, $m) { $maximum = 0; $flag = 0; for($i = 0; $i < $n; $i++) for($j = 0; $j < $m; $j++) // Find maximum element in // a matrix if($maximum < $mat[$i][$j]) $maximum = $mat[$i][$j]; // Take 1-D array of (maximum + 1) // size $b = array(); for($j = 0; $j < $maximum + 1; $j++) $b[$j] = 0; for($i = 0 ; $i < $n; $i++) for($j = 0; $j < $m; $j++) $b[$mat[$i][$j]]++; // print unique element for($i = 1; $i <= $maximum; $i++) if($b[$i] == 1) echo "$i "; $flag = 1; if(!$flag) { echo "No unique element in the matrix"; } } // Driver Code $mat = array(array(1, 2, 3, 20), array(5, 6, 20, 25), array(1, 3, 5, 6), array(6, 7, 8, 15)); // function that calculate unique element unique($mat, $R, $C); // This code is contributed by iAyushRaj ?> ``` **输出**： ``` 2 7 8 25 15 ``` * * * * * *