Trapping rainwater

others/BoyerMoore/BoyerMooreVoting.cpp

@@ -0,0 +1,43 @@
+#include <iostream>
+using namespace std;
+// Function to find majority element
+int findMajority(int arr[], int n)
+{
+    int i, candidate = -1, votes = 0;
+    // Finding majority candidate
+    for (i = 0; i < n; i++)
+    {
+        if (votes == 0)
+        {
+            candidate = arr[i];
+            votes = 1;
+        }
+        else
+        {
+            if (arr[i] == candidate)
+                votes++;
+            else
+                votes--;
+        }
+    }
+    int count = 0;
+    // Checking if majority candidate occurs more than n/2
+    // times
+    for (i = 0; i < n; i++)
+    {
+        if (arr[i] == candidate)
+            count++;
+    }
+
+    if (count > n / 2)
+        return candidate;
+    return -1;
+}
+int main()
+{
+    int arr[] = {1, 1, 1, 1, 2, 3, 4};
+    int n = sizeof(arr) / sizeof(arr[0]);
+    int majority = findMajority(arr, n);
+    cout << " The majority element is : " << majority;
+    return 0;
+}

others/TrappingRainwater/TrappingRainwater.cpp

@@ -0,0 +1,41 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int findWater(int arr[], int n)
+{
+    int left[n];
+    int right[n];
+
+    // Initialize result
+    int water = 0;
+
+    // Fill left array
+    left[0] = arr[0];
+    for (int i = 1; i < n; i++)
+        left[i] = max(left[i - 1], arr[i]);
+
+    // Fill right array
+    right[n - 1] = arr[n - 1];
+    for (int i = n - 2; i >= 0; i--)
+        right[i] = max(right[i + 1], arr[i]);
+
+    for (int i = 1; i < n - 1; i++)
+    {
+        int var = min(left[i - 1], right[i + 1]);
+        if (var > arr[i])
+        {
+            water += var - arr[i];
+        }
+    }
+
+    return water;
+}
+
+// Driver program
+int main()
+{
+    int arr[] = {0, 1, 0, 2, 1, 0, 1, 3, 2, 1, 2, 1};
+    int n = sizeof(arr) / sizeof(arr[0]);
+    cout << findWater(arr, n);
+    return 0;
+}