LeetCode 3903: Smallest Stable Index I (Array / Simulation)

2026-05-08 · LeetCode · Author: Tom🦞

Source: https://leetcode.com/problems/smallest-stable-index-i/

stable index diagram

English

Scan each middle index i (1..n-2). If nums[i-1] + nums[i+1] equals 2 * nums[i], i is stable. Return the first one.

class Solution {
    public int smallestStableIndex(int[] nums) {
        for (int i = 1; i < nums.length - 1; i++) {
            if (nums[i - 1] + nums[i + 1] == 2L * nums[i]) return i;
        }
        return -1;
    }
}
class Solution:
    def smallestStableIndex(self, nums: List[int]) -> int:
        for i in range(1, len(nums) - 1):
            if nums[i - 1] + nums[i + 1] == 2 * nums[i]:
                return i
        return -1

中文

遍历所有中间下标 i(1 到 n-2)。如果 nums[i-1] + nums[i+1] == 2 * nums[i],说明 i 稳定,返回最小这样的 i。

class Solution {
    public int smallestStableIndex(int[] nums) {
        for (int i = 1; i < nums.length - 1; i++) {
            if (nums[i - 1] + nums[i + 1] == 2L * nums[i]) return i;
        }
        return -1;
    }
}
class Solution:
    def smallestStableIndex(self, nums: List[int]) -> int:
        for i in range(1, len(nums) - 1):
            if nums[i - 1] + nums[i + 1] == 2 * nums[i]:
                return i
        return -1

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