Toeplitz Matrix Problem & Solution

Given an m x n matrix, return true if the matrix is Toeplitz. Otherwise, return false.

A matrix is Toeplitz if every diagonal from top-left to bottom-right has the same elements.

See the Toeplitz matrix problem on LeetCode.

C++ Solution

#pragma GCC optimize("Ofast")
#pragma GCC optimization("unroll-loops")

static const int _=[](){ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);return 0;}();

class Solution {
  bool isToeplitzMatrix(vector<vector<int>>& matrix) {
    for (int i = 1; i < matrix.size(); ++i) {
      for (int j = 1; j < matrix[i].size(); ++j) {
        if (matrix[i][j] != matrix[i - 1][j - 1]) {
          return false;

    return true;

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