5 problems solved.

lintcoder · lintcoder · commit 7f089b74cb4a · 2021-11-21T11:46:24.000+08:00
diff --git a/src/1925.cpp b/src/1925.cpp
@@ -0,0 +1,26 @@
+int countTriples(int n) {
+        int ct = 0;
+        vector<int> vec(n, 0);
+        for (int i = 1; i <= n; ++i)
+            vec[i-1] = i*i;
+        
+        int lim = int(n/sqrt(2))+1;
+        for (int i = 0; i < lim; ++i)
+        {
+            for (int j = i; j < n; ++j)
+            {
+                for (int k = j+1; k < n; ++k)
+                {
+                    if (vec[k] == vec[i]+vec[j])
+                    {
+                        if (i != j)
+                            ct += 2;
+                        else
+                            ++ct;
+                    }
+                }
+            }  
+        }
+        
+        return ct;
+    }
diff --git a/src/2068.cpp b/src/2068.cpp
@@ -0,0 +1,19 @@
+bool checkAlmostEquivalent(string word1, string word2) {
+        int len = word1.size();
+        vector<int> vec1(26, 0);
+        vector<int> vec2(26, 0);
+        
+        for (int i = 0; i < len; ++i)
+        {
+            vec1[word1[i]-'a']++;
+            vec2[word2[i]-'a']++;
+        }
+        
+        for (int i = 0; i < 26; ++i)
+        {
+            if (abs(vec1[i]-vec2[i]) > 3)
+                return false;
+        }
+        
+        return true;
+    }
diff --git a/src/2074.cpp b/src/2074.cpp
@@ -0,0 +1,87 @@
+ListNode* reverseEvenLengthGroups(ListNode* head) {
+        if (head == nullptr || head->next == nullptr || head->next->next == nullptr)
+            return head;
+        
+        int ct = 0;
+        ListNode* p = head;
+        while (p != nullptr)
+        {
+            ++ct;
+            p = p->next;
+        }
+        
+        int lim = 2*ct;
+        int n = sqrt(lim);
+        int tmp = n*(n+1);
+        int r = 0;
+        if (tmp == lim)
+            ;
+        else if (tmp < lim)
+            r = ct-tmp/2;
+        else
+        {
+            r = ct-n*(n-1)/2;
+            --n;
+        }
+        
+        ListNode* pre = head;
+        ListNode* post = pre->next;
+        ListNode* cur = post->next;
+        int i = 2;
+        bool flag = true;
+        while (i <= n)
+        {
+            if (flag)
+            {
+                p = post;
+                for (int j = 1; j < i; ++j)
+                {
+                    pre->next = cur;
+                    ListNode* tmp = cur->next;
+                    cur->next = p;
+                    p = cur;
+                    cur = tmp;
+                }
+                post->next = cur;
+            }
+            else
+            {
+                for (int j = 0; j < i; ++j)
+                {
+                    pre = cur;
+                    cur = cur->next;
+                }
+                post = cur;
+                if (cur != nullptr)
+                    cur = cur->next;
+            }
+            flag = !flag;
+            ++i;
+        }
+        
+        if (r > 0)
+        {
+            if (!flag)
+            {
+                pre = post;
+                post = post->next;
+                if (cur != nullptr)
+                    cur = cur->next;
+            }
+            if (r%2 == 0)
+            {
+                p = post;
+                for (int j = 1; j < r; ++j)
+                {
+                    pre->next = cur;
+                    ListNode* tmp = cur->next;
+                    cur->next = p;
+                    p = cur;
+                    cur = tmp;
+                }
+                post->next = cur;
+            }
+        }
+        
+        return head;
+    }
diff --git a/src/228.cpp b/src/228.cpp
@@ -0,0 +1,29 @@
+vector<string> summaryRanges(vector<int>& nums) {
+        int len = nums.size();
+        if (len == 0)
+            return {};
+        vector<string> res;
+        
+        int i = 0, j = 0;
+        while (j < len-1)
+        {
+            if (nums[j] == nums[j+1]-1)
+                ++j;
+            else
+            {
+                if (i == j)
+                    res.push_back(to_string(nums[i]));
+                else
+                    res.push_back(to_string(nums[i]) + "->" + to_string(nums[j]));
+                i = j+1;
+                j = i;
+            }
+        }
+        
+        if (i == j)
+            res.push_back(to_string(nums[i]));
+        else
+            res.push_back(to_string(nums[i]) + "->" + to_string(nums[j]));
+        
+        return res;
+    }
diff --git a/src/338.cpp b/src/338.cpp
@@ -0,0 +1,26 @@
+vector<int> countBits(int num) {
+        int binarr[32] = {0};
+        int ct = 0;
+        vector<int> res(num+1, 0);
+        
+        for (int i = 0; i < num; ++i)
+        {
+            for (int j = 0; j < 32; ++j)
+            {
+                if (binarr[j] == 0)
+                {
+                    ++ct;
+                    res[i+1] = ct;
+                    binarr[j] = 1;
+                    break;
+                }
+                else
+                {
+                    binarr[j] = 0;
+                    --ct;
+                }
+            }
+        }
+        
+        return res;
+    }
