leetcode167

public class Solution {
    public int[] TwoSum(int[] numbers, int target) {
        Dictionary<int, int> dic = new Dictionary<int, int>();
            int count = numbers.Count();
            List<KeyValuePair<int, int>> list = new List<KeyValuePair<int, int>>();

            for (int i = 0; i < count; i++)
            {
                if (!dic.ContainsKey(numbers[i]))
                {
                    dic.Add(numbers[i], i);
                    list.Add(new KeyValuePair<int, int>(numbers[i], i));
                }
            }

            int[] ary = new int[2];

            for (int i = 0; i < list.Count; i++)
            {
                for (int j = i; j < list.Count; j++)
                {
                    var d1 = list[i];
                    var d2 = list[j];
                    if (d1.Key + d1.Key == target && d2.Value - d1.Value > 1)
                    {
                        ary[0] = d1.Value + 1;
                        ary[1] = d1.Value + 2;
                        return ary;
                    }
                    else if (i != j && d1.Key + d2.Key == target)
                    {
                        ary[0] = d1.Value + 1;
                        ary[1] = d2.Value + 1;
                        return ary;
                    }
                }
            }

            return ary;
    }
}

 https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/#/description

补充一个“双指针”思想的解决方案，使用python实现：

class Solution:
    def twoSum(self, numbers: 'List[int]', target: 'int') -> 'List[int]':
        i=0
        j=len(numbers)-1
        while numbers[i] + numbers[j] != target:
            if numbers[i] + numbers[j]>target:
                j-=1
            else:
                i+=1

        return [i+1,j+1]

 

Java版：

class Solution {
    public int[] twoSum(int[] numbers, int target) {
        int l = numbers.length;
        int i=0;
        int j=l-1;
        while(i < j){
            int cursum = numbers[i] + numbers[j];
            if(cursum < target){
                i++;
            }else if(cursum > target){
                j--;
            }else{
                return new int[]{i+1,j+1};
            }
        }
        return new int[]{0,0};
    }
}