1331. 数组序号转换
作者:互联网
这个朋友写的非常棒:https://leetcode-cn.com/problems/rank-transform-of-an-array/solution/c-by-eric-345-63/
class Solution {
public:
//二分查找
int binary_search(vector<int>& arr, int num)
{
int left = 0;
int right = arr.size() - 1;
while (left <= right)
{
int mid = left + ((right - left) >> 1);
if (arr.at(mid) == num)
{
return mid;
}
else if (num < arr.at(mid))
{
right = mid - 1;
}
else
{
left = mid + 1;
}
}
return -1;
}
vector<int> arrayRankTransform(vector<int>& arr) {
if (arr.empty())
{
return arr;
}
//拷贝、排序
vector<int> arr_copy(arr.begin(), arr.end());
sort(arr_copy.begin(), arr_copy.end());
//去重
vector<int> v;
v.reserve(arr_copy.size());
v.push_back(arr_copy.at(0));
for (int i = 1; i < arr_copy.size(); ++i)
{
if (arr_copy.at(i) != v.back())
{
v.push_back(arr_copy.at(i));
}
}
//遍历原数组,在排序去重后的数组中二分查找
vector<int> res;
res.reserve(arr.size());
res.push_back(binary_search(v, arr.at(0)) + 1);
for (int i = 0; i < arr.size() - 1; ++i)
{
if (arr.at(i + 1) == arr.at(i)) //相同的数只查找一次
{
res.push_back(res.back());
}
else
{
res.push_back(binary_search(v, arr.at(i + 1)) + 1);
}
}
return res;
}
};
作者:eric-345
链接:https://leetcode-cn.com/problems/rank-transform-of-an-array/solution/c-by-eric-345-63/
来源:力扣(LeetCode)
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标签:arr,int,res,1331,back,mid,数组,序号,copy 来源: https://blog.csdn.net/weixin_43087913/article/details/111188620