From 76806ab8ac49ff2f959eb65309ce0773b48b35b8 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Mon, 22 Feb 2021 23:52:44 +0800
Subject: import(solutions): Add problem 766.

---
 works/solutions/cpp/766-2.cpp | 20 ++++++++++++++++++++
 works/solutions/cpp/766.cpp   | 44 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+)
 create mode 100644 works/solutions/cpp/766-2.cpp
 create mode 100644 works/solutions/cpp/766.cpp

diff --git a/works/solutions/cpp/766-2.cpp b/works/solutions/cpp/766-2.cpp
new file mode 100644
index 0000000..79a0cc8
--- /dev/null
+++ b/works/solutions/cpp/766-2.cpp
@@ -0,0 +1,20 @@
+#include <vector>
+
+using std::vector;
+
+class Solution {
+public:
+  bool isToeplitzMatrix(vector<vector<int>> &matrix) {
+    int row_count = matrix.size();
+    int col_count = matrix.front().size();
+
+    for (int i = 1; i < row_count; i++) {
+      for (int j = 1; j < col_count; j++) {
+        if (matrix[i][j] != matrix[i - 1][j - 1])
+          return false;
+      }
+    }
+
+    return true;
+  }
+};
\ No newline at end of file
diff --git a/works/solutions/cpp/766.cpp b/works/solutions/cpp/766.cpp
new file mode 100644
index 0000000..3e8a015
--- /dev/null
+++ b/works/solutions/cpp/766.cpp
@@ -0,0 +1,44 @@
+#include <algorithm>
+#include <vector>
+
+using std::vector;
+
+class Solution {
+public:
+  bool isToeplitzMatrix(vector<vector<int>> &matrix) {
+    int row_count = matrix.size();
+    int col_count = matrix.front().size();
+
+    if (matrix.size() == 1)
+      return true;
+    if (matrix.front().size() == 1)
+      return true;
+
+    // offset = col - row
+    // max(offset) = row_count - 2
+    // min(offset) = -(col_count - 2)
+    for (int offset = -(col_count - 2); offset <= (row_count - 2); offset++) {
+      int row, col;
+      if (offset >= 0) {
+        row = offset;
+        col = 0;
+      } else {
+        row = 0;
+        col = -offset;
+      }
+
+      int value = matrix[row][col];
+      row++;
+      col++;
+
+      while (row < row_count && col < col_count) {
+        if (matrix[row][col] != value) {
+          return false;
+        }
+        row++;
+        col++;
+      }
+    }
+    return true;
+  }
+};
-- 
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