Create 1538.Guess-the-Majority-in-a-Hidden-Array.cpp

Others/1538.Guess-the-Majority-in-a-Hidden-Array/1538.Guess-the-Majority-in-a-Hidden-Array.cpp

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+/**
+ * // This is the ArrayReader's API interface.
+ * // You should not implement it, or speculate about its implementation
+ * class ArrayReader {
+ *   public:
+ *     // Compares 4 different elements in the array
+ *     // return 4 if the values of the 4 elements are the same (0 or 1).
+ *     // return 2 if three elements have a value equal to 0 and one element has value equal to 1 or vice versa.
+ *     // return 0 : if two element have a value equal to 0 and two elements have a value equal to 1.
+ *     int query(int a, int b, int c, int d);
+ *
+ *     // Returns the length of the array
+ *     int length();
+ * };
+ */
+
+class Solution {
+public:
+    int guessMajority(ArrayReader &reader) 
+    {
+        int n = reader.length();
+        int base = reader.query(0,1,2,3);        
+        int count0 = 1, count1 = 0;
+        int idxDiff = -1;
+        for (int i=4; i<n; i++) // check arr[i] == arr[0] ?
+        {
+            if (base == reader.query(1,2,3,i))
+                count0 += 1;
+            else
+            {
+                count1 += 1;
+                idxDiff = i;
+            }
+
+        }
+
+        if (reader.query(0,2,3,4) == reader.query(1,2,3,4)) // check arr[1] == arr[0]
+            count0 += 1;
+        else
+        {
+            count1 += 1;
+            idxDiff = 1;
+        }
+
+
+        if (reader.query(0,1,3,4) == reader.query(1,2,3,4)) // check arr[2] == arr[0]
+            count0 += 1;
+        else
+        {
+            count1 += 1;
+            idxDiff = 2;
+        }
+
+
+        if (reader.query(0,1,2,4) == reader.query(1,2,3,4)) // check arr[3] == arr[0]
+            count0 += 1;
+        else
+        {
+            count1 += 1;
+            idxDiff = 3;
+        }
+
+        if (count0>count1) return 0;
+        else if (count0<count1) return idxDiff;
+        else return -1;                
+
+    }
+};