167. 两数之和 II - 输入有序数组

中等

题目描述

解法一：遍历 + 二分查找

class Solution {
    public int[] twoSum(int[] numbers, int target) {
		int[] res = new int[2];
		for(int i = 0;i < numbers.length;i++) {
			int temp;
			if((temp = Arrays.binarySearch(numbers, i + 1, numbers.length, target - numbers[i])) > 0) {
				res[0] = i + 1;
				res[1] = temp + 1;
				return res;		
			}
		}
		return null;
    }
}

解法二：双指针

通过双指针向中间遍历

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