Merge pull request doocs#66 from limbowandering/master

add solutions in javascript

Author: yanglbme

solution/013.Roman to Integer/Solution.js

@@ -0,0 +1,20 @@
+const romanToInt = function(s){
+  const map = {
+    'I' : 1,
+    'V' : 5,
+    'X' : 10,
+    'L' : 50,
+    'C' : 100,
+    'D' : 500,
+    'M' : 1000
+  };
+  let sum = 0;
+  for(let i = 0; i < s.length;i++){
+    if(map[s[i]] < map[s[i+1]]){
+      sum-=map[s[i]];
+    }else{
+      sum+=map[s[i]];
+    }
+  }
+  return sum;
+};

solution/118.Pascal's Triangle/Solution.js

@@ -0,0 +1,14 @@
+const generate = function(numRows){
+  let arr = [];
+  for(let i = 0; i < numRows; i++){
+    let row = [];
+    row[0]=1;
+    row[i] = 1;
+
+    for(let j = 1; j < row.length - 1; j++){
+      row[j] = arr[i-1][j-1] + arr[i-1][j];
+    }
+    arr.push(row);
+  }
+  return arr;
+}

solution/155.Min Stack/README.md

@@ -62,4 +62,74 @@ class MinStack {
  * int param_3 = obj.top();
  * int param_4 = obj.getMin();
  */
-```
+```
+
+
+然后还可以再优化一点点, 就是在辅助栈存最小值的索引, 这样可以避免辅助栈的大量的重复元素的情况. 
+
+``` JavaScript
+/**
+ * initialize your data structure here.
+ */
+const MinStack = function() {
+  this.arr = [];
+  this.help = [];  
+};
+
+/** 
+ * @param {number} x
+ * @return {void}
+ */
+MinStack.prototype.push = function(x) {
+    this.arr.push(x);
+    if(this.help.length === 0){
+      this.help.push(0);
+    }else{
+      let min = this.getMin();
+      if(x < min){
+        this.help.push(this.arr.length-1);
+      }
+    }
+};
+
+/**
+ * @return {void}
+ */
+MinStack.prototype.pop = function() {
+    if(this.arr.length === 0){
+      throw new Error('???');
+    }
+    if(this.arr.length - 1 === this.help[this.help.length - 1]){
+      this.help.pop();
+    }
+    this.arr.pop();
+};
+
+/**
+ * @return {number}
+ */
+MinStack.prototype.top = function() {
+    return this.arr[this.arr.length-1];
+};
+
+/**
+ * @return {number}
+ */
+MinStack.prototype.getMin = function() {
+    if(this.arr.length === 0){
+      throw new Error("???");
+    }
+    return this.arr[this.help[this.help.length-1]];
+};
+
+/** 
+ * Your MinStack object will be instantiated and called as such:
+ * var obj = Object.create(MinStack).createNew()
+ * obj.push(x)
+ * obj.pop()
+ * var param_3 = obj.top()
+ * var param_4 = obj.getMin()
+ */
+
+```
+

solution/155.Min Stack/Solution.js

@@ -0,0 +1,62 @@
+/**
+ * initialize your data structure here.
+ */
+const MinStack = function() {
+  this.arr = [];
+  this.help = [];  
+};
+
+/** 
+ * @param {number} x
+ * @return {void}
+ */
+MinStack.prototype.push = function(x) {
+    this.arr.push(x);
+    if(this.help.length === 0){
+      this.help.push(0);
+    }else{
+      let min = this.getMin();
+      if(x < min){
+        this.help.push(this.arr.length-1);
+      }
+    }
+};
+
+/**
+ * @return {void}
+ */
+MinStack.prototype.pop = function() {
+    if(this.arr.length === 0){
+      throw new Error('???');
+    }
+    if(this.arr.length - 1 === this.help[this.help.length - 1]){
+      this.help.pop();
+    }
+    this.arr.pop();
+};
+
+/**
+ * @return {number}
+ */
+MinStack.prototype.top = function() {
+    return this.arr[this.arr.length-1];
+};
+
+/**
+ * @return {number}
+ */
+MinStack.prototype.getMin = function() {
+    if(this.arr.length === 0){
+      throw new Error("???");
+    }
+    return this.arr[this.help[this.help.length-1]];
+};
+
+/** 
+ * Your MinStack object will be instantiated and called as such:
+ * var obj = Object.create(MinStack).createNew()
+ * obj.push(x)
+ * obj.pop()
+ * var param_3 = obj.top()
+ * var param_4 = obj.getMin()
+ */

solution/384.Shuffle an Array/Solution.js

@@ -0,0 +1,36 @@
+/**
+ * @param {number[]} nums
+ */
+const Solution = function(nums) {
+  this.nums = nums || [];
+};
+
+/**
+* Resets the array to its original configuration and return it.
+* @return {number[]}
+*/
+Solution.prototype.reset = function() {
+  return this.nums;
+};
+
+/**
+* Returns a random shuffling of the array.
+* @return {number[]}
+*/
+Solution.prototype.shuffle = function() {
+  let a = this.nums.slice();
+  for(let i = 0; i < a.length; i++){
+    let rand = Math.floor(Math.random() * (a.length - i)) + i;
+    let tmp = a[i];
+    a[i] = a[rand];
+    a[rand] = tmp;
+  }
+  return a;
+};
+
+/** 
+* Your Solution object will be instantiated and called as such:
+* var obj = Object.create(Solution).createNew(nums)
+* var param_1 = obj.reset()
+* var param_2 = obj.shuffle()
+*/

solution/929.Unique Email Addresses/Solution.js

@@ -0,0 +1,40 @@
+const numUniqueEmails2 = function(emails){
+  const emailFilter = function(str){
+    let index = str.search(/@/);
+    let s = str.substring(0,index);
+    let s2 = str.substring(index+1,str.length);
+    let res = '';
+    for(let i = 0; i < s.length; i++){
+      if(s[i] === '+') break;
+      if(s[i] === '.') continue;
+      res = res+s[i];
+    }
+    return res+s2;
+  }
+
+  let arr = [];
+  for(let i = 0; i < emails.length; i++){
+    let t = emailFilter(emails[i]);
+    if(arr.indexOf(t) === -1){
+      arr.push(t);
+    }
+  }
+  return arr.length;
+};
+
+const numUniqueEmails = function(emails){
+  let arr = emails.map(str=>{
+    let index = str.search(/@/);
+    let s = str.substring(0,index);
+    let s2 = str.substring(index+1,str.length);
+    let res = '';
+    for(let i = 0; i < s.length; i++){
+      if(s[i] === '+') break;
+      if(s[i] === '.') continue;
+      res = res+s[i];
+    }
+    return res+s2;
+  });
+  let set = new Set(arr);
+  return set.size;
+}

solution/930.Binary Subarrays With Sum/Solution.js

@@ -0,0 +1,26 @@
+const numSubarrayWithSum = function(A,S){
+  let count = 0;
+  for(let i = 0; i < A.length; i++){
+    if(A[i] === 1) count++;
+  }
+  if(S>count) return 0;
+  let count2 = 0;
+  let res = 0;
+  for(let i = 0; i < A.length; i++){
+    if(S > count- count2) break;
+    let t = 0;
+    for(let j = i; j < A.length; j++){
+      t += A[j];
+      if(t === S){
+        res++;
+        for(let k = j+1; k < A.length; k++){
+          if(A[k] === 0) res++;
+          else break;
+        }
+        break;
+      }
+    }
+    if(A[i] === 1) count2++;
+  }
+  return res;
+};