5 problems solved.

lintcoder · lintcoder · commit b4d2fdc1eced · 2022-01-11T20:38:43.000+08:00
diff --git a/src/108.cpp b/src/108.cpp
@@ -0,0 +1,18 @@
+TreeNode* sortedArrayToBST(vector<int>& nums) {
+        int len = nums.size();
+        return generate(nums, 0, len-1); 
+    }
+    
+    TreeNode* generate(vector<int>& nums, int p, int q)
+    {
+        TreeNode* node = nullptr;
+        if (p <= q)
+        {
+            int lim = (p+q)/2;
+            node = new TreeNode(nums[lim]);
+            node->left = generate(nums, p, lim-1);
+            node->right = generate(nums, lim+1, q);
+        }
+        
+        return node;
+    }
diff --git a/src/2124.cpp b/src/2124.cpp
@@ -0,0 +1,15 @@
+bool checkString(string s) {
+        int len = s.size();
+        int i = 0;
+        while (i < len && s[i] == 'a')
+            ++i;
+        if (i >= len-1)
+            return true;
+        for (; i < len; ++i)
+        {
+            if (s[i] == 'a')
+                return false;
+        }
+        
+        return true;
+    }
diff --git a/src/2125.cpp b/src/2125.cpp
@@ -0,0 +1,32 @@
+int numberOfBeams(vector<string>& bank) {
+        int row = bank.size();
+        if (row == 1)
+            return 0;
+        int col = bank[0].size();
+        vector<int> devices(row, 0);
+        for (int i = 0; i < row; ++i)
+        {
+            for (int j = 0; j < col; ++j)
+            {
+                if (bank[i][j] == '1')
+                    devices[i]++;
+            }
+        }
+        
+        int i = 0, j = 1;
+        int res = 0;
+        while (i < row-1 && devices[i] == 0)
+            ++i;
+        while (i < row-1)
+        {
+            j = i+1;
+            while (j < row && devices[j] == 0)
+                ++j;
+            if (j == row)
+                break;
+            res += devices[i]*devices[j];
+            i = j;
+        }
+        
+        return res;
+    }
diff --git a/src/2129.cpp b/src/2129.cpp
@@ -0,0 +1,26 @@
+string capitalizeTitle(string title) {
+        int len = title.size();
+        int i = 0, pos = 0;
+        int n = 0;
+        while (i < len)
+        {
+            if (title[i] != ' ')
+            {
+                title[i] = tolower(title[i]);
+                ++n;
+            }
+            else
+            {
+                if (n > 2)
+                    title[pos] = toupper(title[pos]);
+                n = 0;
+                pos = i+1;
+            }
+            ++i;
+        }
+        
+        if (n > 2)
+            title[pos] = toupper(title[pos]);
+        
+        return title;
+    }
diff --git a/src/2133.cpp b/src/2133.cpp
@@ -0,0 +1,37 @@
+bool checkValid(vector<vector<int>>& matrix) {
+        int n = matrix.size();
+        vector<int> flag(n, 0);
+        for (int i = 0; i < n; ++i)
+        {
+            flag.assign(n, 0);
+            int ct = 0;
+            for (int j = 0; j < n; ++j)
+            {
+                if (flag[matrix[i][j]-1] == 0)
+                {
+                    flag[matrix[i][j]-1] = 1;
+                    ++ct;
+                }
+            }
+            if (ct != n)
+                return false;
+        }
+        
+        for (int i = 0; i < n; ++i)
+        {
+            flag.assign(n, 0);
+            int ct = 0;
+            for (int j = 0; j < n; ++j)
+            {
+                if (flag[matrix[j][i]-1] == 0)
+                {
+                    flag[matrix[j][i]-1] = 1;
+                    ++ct;
+                }
+            }
+            if (ct != n)
+                return false;
+        }
+        
+        return true;
+    }
