Trapping rainwater problem

// C++ implementation of the approach

#include <bits/stdc++.h>
using namespace std;

// Function to return the maximum
// water that can be stored
int maxWater(int arr[], int n)
{
	// To store the maximum water
	// that can be stored
	int res = 0;

	// For every element of the array
	for (int i = 1; i < n - 1; i++) {

		// Find the maximum element on its left
		int left = arr[i];
		for (int j = 0; j < i; j++)
			left = max(left, arr[j]);

		// Find the maximum element on its right
		int right = arr[i];
		for (int j = i + 1; j < n; j++)
			right = max(right, arr[j]);

		// Update the maximum water
		res = res + (min(left, right) - arr[i]);
	}

	return res;
}

// Driver code
int main()
{
	int arr[] = { 0, 1, 0, 2, 1, 0, 1, 3, 2, 1, 2, 1 };
	int n = sizeof(arr) / sizeof(arr[0]);

	cout << maxWater(arr, n);

	return 0;
}