747. Largest Number At Least Twice of Others
https://leetcode.com/problems/largest-number-at-least-twice-of-others/description/
class Solution { public: int dominantIndex(vector<int>& nums) { if (nums.size() == 0) return -1; int max1 = nums[0], max2, max1index = 0, max2index = -1; for (int i = 1; i < nums.size(); i++) { if (nums[i] >= max1) { // we don't need to update max1 when it == nums[i] only for this problem if (nums[i] > max1) { max2 = max1; max2index = max1index; max1 = nums[i]; max1index = i; } } else if (max2index < 0 || nums[i] > max2) { max2 = nums[i]; max2index = i; } } return (max2index < 0 || max1 >= 2 * max2) ? max1index : -1; } };