42 lines
917 B
C++
42 lines
917 B
C++
/*
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* @Description:
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* @Version: 1.0
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* @Autor: zhuyijun
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* @Date: 2021-12-21 13:33:03
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* @LastEditTime: 2021-12-21 13:51:30
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*/
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//二分查找
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/*
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给定一个 n 个元素有序的（升序）整型数组 nums 和一个目标值 target
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，写一个函数搜索 nums 中的 target，如果目标值存在返回下标，否则返回 -1。
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示例 1:
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输入: nums = [-1,0,3,5,9,12], target = 9
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输出: 4
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解释: 9 出现在 nums 中并且下标为 4
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*/
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#include <bits/stdc++.h>
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using namespace std;
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int search(vector<int>& nums, int target) {
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int low = 0, high = nums.size() - 1;
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while (low <= high) {
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int mid = (high - low) / 2 + low;
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int num = nums[mid];
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if (num == target) {
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return mid;
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} else if (num > target) {
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high = mid - 1;
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} else {
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low = mid + 1;
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}
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}
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return -1;
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}
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int main() {
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vector<int> li = {1, 2, 3, 4, 5, 6, 7};
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cout << search(li, 1);
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return 0;
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} |