message: Update largest-magic-square.cpp
diff: @@ -15,7 +15,7 @@ public:
  for (int l = min(size(grid), size(grid[0])); l >= 1; --l) {
  for (int i = 0; i + l - 1 < size(grid); ++i) {
  for (int j = 0; j + l - 1 < size(grid[0]); ++j) {
  - if (valid(grid, prefix_row, prefix_col, l, i, j)) {
  + if (check(grid, prefix_row, prefix_col, l, i, j)) {
  return l;
  }
  }
  @@ -25,7 +25,7 @@ public:
  }
  private:
  - bool valid(const vector<vector<int>>& grid,
  + bool check(const vector<vector<int>>& grid,
  const vector<vector<int>>& prefix_row,
  const vector<vector<int>>& prefix_col,
  int l, int i, int j) {
  