leetcode刷题_两数之和 II - 输入有序数组

题目描述

 java解决方法

class Solution {
    public int[] twoSum(int[] numbers, int target) {
        int index1 = 0;
        int index2 = numbers.length - 1;
        int[] index = new int[2];
        while(index1 < index2)
        {
            if(numbers[index2] + numbers[index1] > target)
            {
                index2--;
            }
            else if(numbers[index2] + numbers[index1] < target)
            {
                index1++;
            }
            else
            {
                index[0] = index1 + 1;
                index[1] = index2 + 1;
                break;
            }
        }
        return index;
    }
}

 C解决方法

/**
 * Note: The returned array must be malloced, assume caller calls free().
 */
int* twoSum(int* numbers, int numbersSize, int target, int* returnSize){
    int *index = NULL;
    int index1 = 0;
    int index2 = numbersSize - 1;
    index = (int*)malloc(2 * sizeof(int));
    while(index1 < index2)
    {
        if(numbers[index1] + numbers[index2] > target)
        {
            index2--;
        }
        else if(numbers[index1] + numbers[index2] < target)
        {
            index1++;
        }
        else
        {
            index[0] = index1 + 1;
            index[1] = index2 + 1;
            break;
        }
    }
    *returnSize = 2;
    return index;
}

返回回去的变量一定要动态开辟内存，因为局部变量保存在栈上，随着函数的生命周期的结束会内存销毁，而动态开辟的内存是在堆上，函数结束，并不会释放该内存。