1.Find Missing and Repeated Values

直接暴力过

class Solution {
public:vector<int> findMissingAndRepeatedValues(vector<vector<int>>& grid) {vector<int> res(2,0);int n = grid.size();unordered_map<int,int> map;for(int i = 0;i < n;i++){for(int j = 0;j < n;j++) map[grid[i][j]]++;}for(int i = 1;i <= pow(n,2);i++){if(map[i] == 2) res[0] = i;if(map[i] == 0) res[1] = i;}return res;}
};

2.Divide Array Into Arrays With Max Difference

排序+判断

class Solution {
public:vector<vector<int>> divideArray(vector<int>& nums, int k) {int n = nums.size();sort(nums.begin(),nums.end());vector<vector<int>> res;for(int i = 0;i < n - 2;i+=3){if(nums[i+1] - nums[i] > k || nums[i+2] - nums[i] > k || nums[i+2] - nums[i] > k) return res;}for(int i = 0;i < n - 2;i+=3){vector<int> tmp;for(int j = i;j < i + 3;j++){tmp.push_back(nums[j]);}res.push_back(tmp);}return res;}
};

3.Minimum Cost to Make Array Equalindromic

中位数贪心+寻找左右最近回文数

class Solution {
public:vector<int> nearestPalindrome(int x){string s = to_string(x);if(s == string(s.rbegin(),s.rend())) return {x,x};int r = x;while(r++){string tmpStr = to_string(r);if(tmpStr == string(tmpStr.rbegin(),tmpStr.rend())) break;}int l = x;while(l--){string tmpStr = to_string(l);if(tmpStr == string(tmpStr.rbegin(),tmpStr.rend())) break;}return {l,r};}long long minimumCost(vector<int>& nums) {long long res1 = 0;long long res2 = 0;double sum = 0;int n = nums.size();sort(nums.begin(),nums.end());int midNum = 0;if(n % 2 == 1) midNum = nums[n/2];else midNum = (nums[n/2] + nums[n/2-1]) / 2;vector<int> paliNum = nearestPalindrome(midNum);for(auto x:nums){res1 += abs(x-paliNum[0]);}for(auto x:nums){res2 += abs(x-paliNum[1]);}return min(res1,res2);}
};