# Common elements in all rows of a given matrix in Python

## Common elements in all rows of a given matrix in Python

Here, on this page, we will discuss the program to find the Common elements in all rows of a given matrix in Python Programming language. ### Algorithm ( Method 1 )

In this algorithm, we will check for every element in the first row, if that is present in other rows or not.

• For checking the presence, take one variable count.
• Now, run a loop from index 1 to M.
• Take a variable flag =0;
• Now, run a loop from index 0 to N, if (x==mat[i][j]) set flag =1 and break the loop.
• After coming out from loop check if(flag==1) set, count++.
• At last, check if count == M-1, print that value.

### Time and Space Complexity :

• Time complexity: O(M*M*N)
• Space complexity: O(1) ### Python Code

Run
```def find(mat, N, M):
for j in range(0, N):
x, count = mat[j], 0

for i in range(1, M):
flag = 0
for k in range(0, N):
if x == mat[i][k]:
flag = 1
mat[i][k] = -1
break
if flag == 1:
count += 1
if count == M - 1:
print(x)

N, M = 4, 4
mat = [[10, 20, 30, 40],
[15, 25, 35, 30],
[27, 30, 37, 48],
[32, 33, 39, 30]]
find(mat, N, M)
```

### Output

`30`

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