LINTCODE——Sliding Window Unique Elements Sum

LINTCODE——Sliding Window Unique Elements Sum

问题：Given an array and a window size that is sliding along the array, find the sum of the count of unique elements in each window.

思路：总体来说不算太难，用一个map进出一个记录一下差值就ok了

class Solution {
public:
/*
* @param : the given array
* @param : the window size
* @return: the sum of the count of unique elements in each window
*/
int slidingWindowUniqueElementsSum(vector<int> nums, int k) {
// write your code here

int n = nums.size();
map<int, int> record;
for(int i = 0 ; i < min(k,n); i++)
record[nums[i]]++;
vector<int> res;
res.push_back(count(record));

for(int i = k; i < n ; i++)
{
int temp = 0;
record[nums[i-k]]--;
record[nums[i]]++;
if(nums[i-k] != nums[i]){
if(record[nums[i-k]] == 1)
temp++;
else if(record[nums[i-k]] == 0)
temp--;

if(record[nums[i]] == 1)
temp++;
else if(record[nums[i]] == 2)
temp--;
}
res.push_back(res[i-k]+temp);

}
int ret = 0;
for(int x : res)
ret += x;

return ret;
}
int count(map<int, int> &record)
{
int num = 0;
for(auto x : record)
{
if(x.second == 1)
num++;
}
return num;
}
};