Given an array of integers that is already sorted in ascending order, find two numbers such that they add up to a specific target number.

The function twoSum should return indices of the two numbers such that they add up to the target, where index1 must be less than index2. Please note that your returned answers (both index1 and index2) are not zero-based.

You may assume that each input would have exactly one solution and you may not use the same element twice.

Input: numbers={2, 7, 11, 15}, target=9
Output: index1=1, index2=2

翻譯：給出一個升序排列的整數數組，找到兩個數，加起來為目標數字

該函數返回加起來為目標數字的兩個數的下標，其中index1小於index2.且index1和index2都不是從0開始（從1開始，所以數組的下標要加一再返回）

假設每個輸入有且只有一個答案，相同元素不能使用兩次。

輸入：numbers={2, 7, 11, 15}, target=9

輸出： index1=1, index2=2

大神答案（titanduan3）：

public int[] twoSum(int[] num, int target) {
    int[] indice = new int[2];
    if (num == null || num.length < 2) return indice;
    int left = 0, right = num.length - 1;
    while (left < right) {
        int v = num[left] + num[right];
        if (v == target) {
            indice[0] = left + 1;
            indice[1] = right + 1;
            break;
        } else if (v > target) {
            right --;
        } else {
            left ++;
        }
    }
    return indice;
}

我自己是用hashmap做的，膜拜大神的答案，思想很重要啊~~~
 

Two Sum II - Input array is sorted