Add Q155, Q160

Author: theFool32

155_MinStack/MinStack.cc

@@ -0,0 +1,28 @@
+class MinStack {
+public:
+    MinStack() {
+    }
+    
+    void push(int x) {
+        m_stack.push(x);
+        if (m_minStack.empty() || m_minStack.top() >= x) m_minStack.push(x);
+    }
+    
+    void pop() {
+        int t = m_stack.top();
+        m_stack.pop();
+        if (t == m_minStack.top()) m_minStack.pop();
+    }
+    
+    int top() {
+        return m_stack.top();
+    }
+    
+    int getMin() {
+        return m_minStack.top();
+    }
+
+private:
+    stack<int> m_stack;
+    stack<int> m_minStack;
+};

160_IntersectionOfTwoLinkedLists/IntersectionOfTwoLinkedLists.cc

@@ -0,0 +1,41 @@
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode(int x) : val(x), next(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) {
+        auto getLenth = [](ListNode *head) {
+            int len = 0;
+            ListNode *p = head;
+            while (p) {
+                ++len;
+                p = p->next;
+            }
+            return len;
+        };
+        int lenA = getLenth(headA);
+        int lenB = getLenth(headB);
+        ListNode *a = headA;
+        ListNode *b = headB;
+        int delta = abs(lenA-lenB);
+        if (lenA>lenB) {
+            while (delta--) {
+                a = a->next;
+            }
+        } else {
+            while (delta--) {
+                b = b->next;
+            }
+        }
+        while (a && a != b) {
+            a = a->next;
+            b = b->next;
+        }
+        return a;
+    }
+};