diff --git a/C++/climbing-stairs.cpp b/C++/climbing-stairs.cpp
index aeb1393..ab0eead 100644
--- a/C++/climbing-stairs.cpp
+++ b/C++/climbing-stairs.cpp
@@ -1,12 +1,50 @@
-// Time:  O(n)
+// Time:  O(logn)
 // Space: O(1)
 
 class Solution {
 public:
-    /**
-     * @param n: An integer
-     * @return: An integer
-     */
+    int climbStairs(int n) {
+        vector<vector<int>> T = {{1, 1},
+                                 {1, 0}};
+        return matrixExpo(T, n)[0][0];
+    }
+
+private:
+    vector<vector<int>> matrixExpo(const vector<vector<int>>& A, int pow) {
+        vector<vector<int>> result(A.size(), vector<int>(A.size()));
+        vector<vector<int>> A_exp(A);
+        for (int i = 0; i < A.size(); ++i) {
+            result[i][i] = 1;
+        }
+        while (pow) {
+            if (pow % 2 == 1) {
+                result = matrixMult(result, A_exp);
+            }
+            A_exp = matrixMult(A_exp, A_exp);
+            pow /= 2;
+        }
+        return result;
+    }
+
+    vector<vector<int>> matrixMult(const vector<vector<int>>& A, const vector<vector<int>>& B) {
+        vector<vector<int>> result(A.size(), vector<int>(A.size()));
+        for (int i = 0; i < A.size(); ++i) {
+            for (int j = 0; j < B[0].size(); ++j) {
+                int64_t entry = 0;
+                for (int k = 0; k < B.size(); ++k) {
+                    entry = (static_cast<int64_t>(A[i][k]) * B[k][j] + entry);
+                }
+                result[i][j] = static_cast<int>(entry);
+            }
+        }
+        return result;
+    }
+};
+
+// Time:  O(n)
+// Space: O(1)
+class Solution2 {
+public:
     int climbStairs(int n) {
         vector<int> steps(3, 0);
         steps[0] = 1;
@@ -17,4 +55,3 @@ class Solution {
         return steps[n % 3];
     }
 };
-
diff --git a/C++/find-peak-element.cpp b/C++/find-peak-element.cpp
index 8b829b6..3e2f561 100644
--- a/C++/find-peak-element.cpp
+++ b/C++/find-peak-element.cpp
@@ -12,10 +12,7 @@ class Solution {
         
         while (left < right) {
             const auto mid = left + (right - left) / 2;
-            if ((mid == 0 || A[mid - 1] < A[mid]) &&
-               (mid + 1 == A.size() || A[mid] > A[mid + 1])) {
-                return mid;
-            } else if (!(mid == 0 || A[mid - 1] < A[mid])) {
+            if (A[mid] > A[mid + 1]) {
                 right = mid;
             } else {
                 left = mid + 1;
diff --git a/README.md b/README.md
index 2ef95fb..0641d31 100644
--- a/README.md
+++ b/README.md
@@ -1,9 +1,9 @@
-# [LintCode](http://www.lintcode.com/en/problem/) ![Language](https://img.shields.io/badge/language-C++%2011-orange.svg) [![License](https://img.shields.io/badge/license-MIT-blue.svg)](./LICENSE.md) ![Progress](https://img.shields.io/badge/progress-289%20%2F%20289-ff69b4.svg)
+# [LintCode](http://www.lintcode.com/en/problem/) ![Language](https://img.shields.io/badge/language-C++11-orange.svg) [![License](https://img.shields.io/badge/license-MIT-blue.svg)](./LICENSE.md) ![Progress](https://img.shields.io/badge/progress-289%20%2F%20289-ff69b4.svg)
 
 Up to date (2016-08-22), there are `289` problems on [LintCode Online Judge](http://lintcode.com/).
 The number of problems is increasing recently.
 Here is the classification of all `289` problems.
-For more problems and solutions, you can see my [LeetCode](https://github.com/kamyu104/LeetCode) repository.
+For more problems and solutions, you can see my [LeetCode-Solutions](https://github.com/kamyu104/LeetCode-Solutions) repository.
 I'll keep updating for full summary and better solutions. Stay tuned for updates.
 
 ## Algorithms
@@ -366,7 +366,7 @@ I'll keep updating for full summary and better solutions. Stay tuned for updates
 |108|[Palindrome Partitioning II](http://lintcode.com/en/problem/palindrome-partitioning-ii/)| [C++](./C++/palindrome-partitioning-ii.cpp)| _O(n^2)_ | _O(n)_ | Medium | LeetCode, EPI | |
 |109|[Triangle](http://lintcode.com/en/problem/triangle/)| [C++](./C++/triangle.cpp)| _O(n)_ | _O(n)_ | Easy | LeetCode, EPI | |
 |110|[Minimum Path Sum](http://lintcode.com/en/problem/minimum-path-sum/)| [C++](./C++/minimum-path-sum.cpp)| _O(m * n)_ | _O(min(m, n))_ | Easy | LeetCode, EPI | |
-|111|[Climbing Stairs](http://lintcode.com/en/problem/climbing-stairs/)| [C++](./C++/climbing-stairs.cpp)| _O(n)_ | _O(1)_ | Easy | LeetCode | |
+|111|[Climbing Stairs](http://lintcode.com/en/problem/climbing-stairs/)| [C++](./C++/climbing-stairs.cpp)| _O(logn)_ | _O(1)_ | Easy | LeetCode | |
 |115|[Unique Paths II](http://lintcode.com/en/problem/unique-paths-ii/)| [C++](./C++/unique-paths-ii.cpp)| _O(m * n)_ | _O(min(m, n))_ | Easy | LeetCode, CTCI | DP, Math |
 |118|[Distinct Subsequences](http://lintcode.com/en/problem/distinct-subsequences/)| [C++](./C++/distinct-subsequences.cpp)| _O(m * n)_ | _O(m)_ | Medium | LeetCode | DP |
 |119|[Edit Distance](http://lintcode.com/en/problem/edit-distance/)| [C++](./C++/edit-distance.cpp)| _O(m * n)_ | _O(min(m, n))_ | Medium | LeetCode, CTCI | DP |