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Commit 3fa279a

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155 solved. (#66)
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‎README.md

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* [717. 1-bit and 2-bit Characters](src/0717_1_bit_and_2_bit_characters/1bitand2bitc.go)
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* [747. Largest Number At Least Twice of Others](./src/0747_largest_number_at_least_twice_of_others/largest_number_at_least_twice_of_others.go)
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### Stack
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* [155. Min Stack](src/0155_min_stack/min_stack.go)
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### String
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* [3. Longest Substring Without Repeating Characters](./src/0003_longest_substring_without_repeating_characters/longest_substring_without_repeating_characters.go)   *`sliding window;`*  *`hash table`*
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* [14. Longest Common Prefix](src/0014_longest_common_prefix/lcp.go)

‎src/0155_min_stack/min_stack.go

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/*
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155. Min Stack
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https://leetcode.com/problems/min-stack/
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Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.
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push(x) -- Push element x onto stack.
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pop() -- Removes the element on top of the stack.
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top() -- Get the top element.
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getMin() -- Retrieve the minimum element in the stack.
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*/
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// time: 2019年01月10日
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package minstack
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// MinStack a stack that supports push, pop, top, and retrieving the minimum element in constant time.
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type MinStack struct {
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data []int
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}
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// Constructor initialize your data structure here.
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func Constructor() MinStack {
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return MinStack{}
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}
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// Push element x onto stack.
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func (s *MinStack) Push(x int) {
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s.data = append(s.data, x)
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}
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// Pop Removes the element on top of the stack.
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func (s *MinStack) Pop() {
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if !s.IsEmpty() {
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s.data = s.data[:s.GetSize()-1]
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}
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}
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// Top Get the top element.
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func (s *MinStack) Top() int {
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//if s.IsEmpty(){
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// return 0
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//}
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// stack must have element.
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return s.data[s.GetSize()-1]
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}
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// GetMin retrieving the minimum element in constant time.
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// time complexity: O(n)
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func (s *MinStack) GetMin() int {
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//if s.IsEmpty() {
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// return 0
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//}
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// stack must have element.
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stackSize := s.GetSize()
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ret := s.data[stackSize-1]
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for i := stackSize - 2; i >= 0; i-- {
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if s.data[i] < ret {
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ret = s.data[i]
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}
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}
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return ret
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}
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// GetSize get size of the stack.
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func (s MinStack) GetSize() int {
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return len(s.data)
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}
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func (s MinStack) IsEmpty() bool {
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return s.GetSize() == 0
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}

‎src/0155_min_stack/min_stack_test.go

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package minstack
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import "testing"
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func TestMinStack(t *testing.T) {
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obj := Constructor()
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obj.Push(-2)
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obj.Push(0)
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obj.Push(-3)
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if res := obj.GetMin(); res != -3 {
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t.Errorf("expected %d, got %d", -3, res)
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}
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obj.Pop()
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if res := obj.Top(); res != 0 {
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t.Errorf("expected %d, got %d", 0, res)
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}
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if res := obj.GetMin(); res != -2 {
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t.Errorf("expected %d, got %d", -2, res)
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}
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}

‎src/README.md

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|0144|[144. Binary Tree Preorder Traversal](0144_binary_tree_preorder_traversal/binary_tree_preorder_traversal.go)|Medium|*`binary tree`*|
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|0150|[150. Evaluate Reverse Polish Notation](0150_evaluate_reverse_polish_notation/evaluate_reverse_polish_notation.go)|Medium|*`stack`*|
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|0153|[153. Find Minimum in Rotated Sorted Array](0153_find_minimum_in_rotated_sorted_array/fmirsa.go)|Medium|*`binary search`*|
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|0155|[155. Min Stack](0155_min_stack/min_stack.go)|Easy|*`stack`*|
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|0165|[165. Compare Version Numbers](0165_compare_version_numbers/compare_version_numbers.go)|Medium|*`string`*|
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|0167|[Two Sum II - Input array is sorted](./0167_two_sum2/two_sum2.go)|Easy|*`对撞指针(双索引)`*|
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|0198|[House Robber](./0198_house_robber/house_robber.go)|Easy|*`memory search;`* *`dynamic programming`*|

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