5 problems solved.

lintcoder · lintcoder · commit 65fedc39abd9 · 2018-11-23T22:29:12.000+08:00
diff --git a/src/225.cpp b/src/225.cpp
@@ -0,0 +1,49 @@
+class Stack {
+    private:
+        deque<int> dq[2];
+        int flag = 0;
+        int topelem;
+        int size = 0;
+public:
+    // Push element x onto stack.
+    void push(int x) {
+        dq[flag].push_back(x);
+        topelem = x;
+        ++size;
+    }
+
+    // Removes the element on top of the stack.
+    void pop() {
+        if (size > 0)
+        {
+            int i = 1;
+            while (i < size - 1)
+            {
+                dq[1 - flag].push_back(dq[flag].front());
+                dq[flag].pop_front();
+                ++i;
+            }
+            if (i == size - 1)
+            {
+                int val = dq[flag].front();
+                dq[1 - flag].push_back(val);
+                dq[flag].pop_front();
+                topelem = val;
+            }
+            dq[flag].pop_front();
+            
+            flag = 1 - flag;
+            --size;
+        }
+    }
+
+    // Get the top element.
+    int top() {
+        return topelem;
+    }
+
+    // Return whether the stack is empty.
+    bool empty() {
+        return size == 0;
+    }
+};
diff --git a/src/434.cpp b/src/434.cpp
@@ -0,0 +1,13 @@
+int countSegments(string s) {
+        int sz = s.size();
+        int i = 0, ct = 0;
+        while (i < sz)
+        {
+            i = s.find_first_not_of(" \t\n", i);
+            if (i == string::npos)
+                break;
+            i = s.find_first_of(" \t\n", i + 1);
+            ++ct;
+        }
+        return ct;
+    }
diff --git a/src/67.cpp b/src/67.cpp
@@ -0,0 +1,39 @@
+string addBinary(string a, string b) {
+        int len1 = a.size();
+        int len2 = b.size();
+        
+        string res(len1 > len2 ? len1 + 1 : len2 + 1, '0');
+        int i = len1 - 1, j = len2 - 1;
+        int ct = 0, k = res.size() - 1;
+        while (i >= 0 && j >= 0)
+        {
+            int sum = a[i] - '0' + b[j] - '0' + ct;
+            res[k] = sum % 2 + '0';
+            --k;
+            --i;
+            --j;
+            ct = sum >> 1 ? 1 : 0;
+        }
+        while (i >= 0)
+        {
+            int sum = a[i] - '0' + ct;
+            res[k] = sum % 2 + '0';
+            --k;
+            --i;
+            ct = sum >> 1 ? 1 : 0;
+        }
+        while (j >= 0)
+        {
+            int sum = b[j] - '0' + ct;
+            res[k] = sum % 2 + '0';
+            --k;
+            --j;
+            ct = sum >> 1 ? 1 : 0;
+        }
+        if (ct > 0)
+            res[k] = ct + '0';
+        if (res[0] == '0')
+            return string(res.begin() + 1, res.end());
+        else
+            return res;
+    }
diff --git a/src/917.cpp b/src/917.cpp
@@ -0,0 +1,20 @@
+string reverseOnlyLetters(string S)
+    {
+        int len = S.size();
+        int i = 0, j = len-1;
+        while (i < j)
+        {
+            while (i < j && isalpha(S[i]) == false)
+                ++i;
+            while (i < j && isalpha(S[j]) == false)
+                --j;
+            if (i < j)
+            {
+                std::swap(S[i], S[j]);
+                ++i;
+                --j;
+            }
+        }
+
+        return S;
+    }
diff --git a/src/942.cpp b/src/942.cpp
@@ -0,0 +1,26 @@
+vector<int> diStringMatch(string S) {
+        int len = S.size()+1;
+        if (len <= 1)
+            return {};
+        
+        vector<int> res(len, 0);
+        int k = len-2;
+        int i = len-1, j = 0;
+        while (k >= 0)
+        {
+            if (S[k] == 'I')
+            {
+                res[k+1] = i;
+                --i;
+            }
+            else
+            {
+                res[k+1] = j;
+                ++j;
+            }
+            --k;
+        }
+        res[0] = i;
+        
+        return res;
+    }
