53 lines
1.2 KiB
C++
53 lines
1.2 KiB
C++
/* Problem: https://leetcode.com/problems/find-peak-element/
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*/
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#include <iostream>
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#include <vector>
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int solution(const std::vector<int> &nums) {
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if (nums.size() == 0) {
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return -1;
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}
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if (nums.size() == 1) {
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return 0;
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};
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long long first = 0, last = nums.size() - 1, pi = last / 2;
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while (true) {
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if (pi == 0) {
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if (nums[pi] > nums[pi + 1]) {
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return pi;
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} else {
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first = pi + 1;
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pi = ((last - first) / 2) + first;
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continue;
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}
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} else if (pi == (long long)nums.size() - 1) {
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if (nums[pi] > nums[pi - 1]) {
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return pi;
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} else {
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last = pi - 1;
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pi = ((last - first) / 2) + first;
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continue;
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}
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}
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if (nums[pi] < nums[pi - 1]) {
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last = pi - 1;
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} else if (nums[pi] < nums[pi + 1]) {
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first = pi + 1;
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} else {
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return pi;
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}
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pi = ((last - first) / 2) + first;
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}
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return pi;
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}
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int main() {
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std::vector<int> nums1 = {1, 2, 3, 1}, nums2 = {1, 2, 1, 3, 5, 6, 4};
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int i1, i2;
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i1 = solution(nums1);
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std::cout << i1 << " : " << nums1[i1] << '\n';
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i2 = solution(nums2);
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std::cout << i2 << " : " << nums2[i2] << '\n';
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} |