Find 2 numbers in an unsorted array equal to a given sum

Question

We need to find pair of numbers in an array whose sum is equal to a given value.

A = {6,4,5,7,9,1,2}

Sum = 10 Then the pairs are - {6,4} ,

Answer 1

https://github.com/clockzhong/findSumPairNumber

#! /usr/bin/env python
import sys
import os
import re


#get the number list
numberListStr=raw_input("Please input your number list (seperated by spaces)...\n")
numberList=[int(i) for i in numberListStr.split()]
print 'you have input the following number list:'
print numberList

#get the sum target value
sumTargetStr=raw_input("Please input your target number:\n")
sumTarget=int(sumTargetStr)
print 'your target is: '
print sumTarget


def generatePairsWith2IndexLists(list1, list2):
    result=[]
    for item1 in list1:
        for item2 in list2:
            #result.append([item1, item2])
            result.append([item1+1, item2+1])
    #print result
    return result

def generatePairsWithOneIndexLists(list1):
    result=[]
    index = 0
    while index< (len(list1)-1):
        index2=index+1
        while index2 < len(list1):
            #result.append([list1[index],list1[index2]])
            result.append([list1[index]+1,list1[index2]+1])
            index2+=1
        index+=1
    return result


def getPairs(numList, target):
    pairList=[]
    candidateSlots=[] ##we have (target-1) slots 

    #init the candidateSlots list
    index=0
    while index < target+1:
        candidateSlots.append(None)
        index+=1

    #generate the candidateSlots, contribute O(n) complexity
    index=0
    while index=0:
            #print 'index:',index
            #print 'numList[index]:',numList[index]     
            #print 'len(candidateSlots):',len(candidateSlots)
            if candidateSlots[numList[index]]==None:
                candidateSlots[numList[index]]=[index]
            else:
                candidateSlots[numList[index]].append(index)
        index+=1

    #print candidateSlots

    #generate the pairs list based on the candidateSlots[] we just created
    #contribute O(target) complexity
    index=0
    while index<=(target/2):
        if candidateSlots[index]!=None and candidateSlots[target-index]!=None:
            if index!=(target-index):
                newPairList=generatePairsWith2IndexLists(candidateSlots[index], candidateSlots[target-index])
            else:
                newPairList=generatePairsWithOneIndexLists(candidateSlots[index])
            pairList+=newPairList
        index+=1

    return pairList

print getPairs(numberList, sumTarget)

I've successfully implemented one solution with Python under O(n+m) time and space cost. The "m" means the target value which those two numbers' sum need equal to. I believe this is the lowest cost could get. Erict2k used itertools.combinations, it'll also cost similar or higher time&space cost comparing my algorithm.