Array problem solutions added

Author: Badhansen

561. Array Partition I.cpp

@@ -0,0 +1,12 @@
+class Solution {
+public:
+    int arrayPairSum(vector<int>& nums) {
+        int sum = 0;
+        sort(nums.begin(), nums.end());
+        int siz = nums.size();
+        for(int i=0; i<siz; i+=2){
+            sum += nums[i];
+        }
+        return sum;
+    }
+};

832. Flipping an Image.cpp

@@ -0,0 +1,14 @@
+class Solution {
+public:
+    vector<vector<int>> flipAndInvertImage(vector<vector<int>>& A) {
+        for(auto &x : A){
+            reverse(x.begin(), x.end());
+            for(auto &y : x){
+                y = !(y & 1);
+            }
+
+        }
+        return A;
+    }
+
+};

905. Sort Array By Parity.cpp

@@ -0,0 +1,20 @@
+class Solution {
+public:
+    vector<int> sortArrayByParity(vector<int>& A) {
+        vector<int> st;
+        deque<int> dt;
+        for(auto x : A){
+            if(x & 1){
+                dt.emplace_back(x);
+            }
+            else{
+                dt.emplace_front(x);
+            }
+        }
+        while(!dt.empty()){
+            st.emplace_back(dt.front());
+            dt.pop_front();
+        }
+        return st;
+    }
+};

977. Squares of a Sorted Array.cpp

@@ -0,0 +1,11 @@
+class Solution {
+public:
+    vector<int> sortedSquares(vector<int>& A) {
+        vector<int> st;
+        for(auto x : A){
+            st.push_back(x * x);
+        }
+        sort(st.begin(), st.end());
+        return st;
+    }
+};