118. Pascal's Triangle.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Given numRows, generate the first numRows of Pascal's triangle.\n",
    "\n",
    "For example, given numRows = 5,\n",
    "Return\n",
    "\n",
    "[\n",
    "     [1],\n",
    "    [1,1],\n",
    "   [1,2,1],\n",
    "  [1,3,3,1],\n",
    " [1,4,6,4,1]\n",
    "]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "class Solution(object):\n",
    "    def generate(self, numRows):\n",
    "        \"\"\"\n",
    "        :type numRows: int\n",
    "        :rtype: List[List[int]]\n",
    "        \"\"\"\n",
    "        \n",
    "        res=[]\n",
    "        if numRows<1:\n",
    "            return res\n",
    "        if numRows==1:\n",
    "            return [[1]]\n",
    "        res=[[1],[1,1]]\n",
    "        if numRows==2:\n",
    "            return res\n",
    "        for i in range(3,numRows+1):\n",
    "            temp=[1]\n",
    "            for j in range(i-2):\n",
    "                temp.append(res[-1][j]+res[-1][j+1])\n",
    "            temp.append(1)\n",
    "            res.append(temp)\n",
    "        return res\n",
    "                "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "s=Solution()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[2]"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "[i for i in range(2,3)]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[[1],\n",
       " [1, 1],\n",
       " [1, 2, 1],\n",
       " [1, 3, 3, 1],\n",
       " [1, 4, 6, 4, 1],\n",
       " [1, 5, 10, 10, 5, 1],\n",
       " [1, 6, 15, 20, 15, 6, 1],\n",
       " [1, 7, 21, 35, 35, 21, 7, 1],\n",
       " [1, 8, 28, 56, 70, 56, 28, 8, 1]]"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s.generate(9)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": []
  }
 ],
 "metadata": {
  "anaconda-cloud": {},
  "kernelspec": {
   "display_name": "Python [default]",
   "language": "python",
   "name": "python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.5.2"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 1
}