We have been given N balloons, each with a number of coins associated with it. On bursting a balloon i, the number of coins gained is equal to A[i-1]*A[i]*A[i+1]. Also, balloons i-1 and i+1 now become adjacent. Find the maximum possible profit earned after bursting all the balloons. Assume an extra 1 at each boundary.
Examples:
Input : 5, 10 Output : 60 Explanation - First Burst 5, Coins = 1*5*10 Then burst 10, Coins+= 1*10*1 Total = 60 Input : 1, 2, 3, 4, 5 Output : 110
A recursive solution is discussed here. We can solve this problem using dynamic programming.
First, consider a sub-array from indices Left to Right(inclusive).
If we assume the balloon at index Last to be the last balloon to be burst in this sub-array, we would say the coined gained to be-A[left-1]*A[last]*A[right+1].
Also, the total Coin Gained would be this value, plus dp[left][last – 1] + dp[last + 1][right], where dp[i][j] means maximum coin gained for sub-array with indices i, j.
Therefore, for each value of Left and Right, we need find and choose a value of Last with maximum coin gained, and update the dp array.
Our Answer is the value at dp[1][N].
C++
// C++ program burst balloon problem #include <bits/stdc++.h> #include <iostream> using namespace std; int getMax( int A[], int N) { // Add Bordering Balloons int B[N + 2]; B[0] = 1; B[N + 1] = 1; for ( int i = 1; i <= N; i++) B[i] = A[i - 1]; // Declare DP Array int dp[N + 2][N + 2]; memset (dp, 0, sizeof (dp)); for ( int length = 1; length < N + 1; length++) { for ( int left = 1; left < N - length + 2; left++) { int right = left + length - 1; // For a sub-array from indices left, right // This innermost loop finds the last balloon burst for ( int last = left; last < right + 1; last++) { dp[left][right] = max(dp[left][right], dp[left][last - 1] + B[left - 1] * B[last] * B[right + 1] + dp[last + 1][right]); } } } return dp[1][N]; } // Driver code int main() { int A[] = { 1, 2, 3, 4, 5 }; // Size of the array int N = sizeof (A) / sizeof (A[0]); // Calling function cout << getMax(A, N) << endl; } // This code is contributed by ashutosh450 |
Java
// Java program to illustrate // Burst balloon problem import java.util.Arrays; class GFG{ public static int getMax( int [] A, int N) { // Add Bordering Balloons int [] B = new int [N + 2 ]; B[ 0 ] = B[N + 1 ] = 1 ; for ( int i = 1 ; i <= N; i++) B[i] = A[i - 1 ]; // Declaring DP array int [][] dp = new int [N + 2 ][N + 2 ]; for ( int length = 1 ; length < N + 1 ; length++) { for ( int left = 1 ; left < N - length + 2 ; left++) { int right = left + length - 1 ; // For a sub-array from indices // left, right. This innermost // loop finds the last balloon burst for ( int last = left; last < right + 1 ; last++) { dp[left][right] = Math.max( dp[left][right], dp[left][last - 1 ] + B[left - 1 ] * B[last] * B[right + 1 ] + dp[last + 1 ][right]); } } } return dp[ 1 ][N]; } // Driver code public static void main(String args[]) { int [] A = { 1 , 2 , 3 , 4 , 5 }; // Size of the array int N = A.length; // Calling function System.out.println(getMax(A, N)); } } // This code is contributed by dadi madhav |
Python3
# Python3 program burst balloon problem. def getMax(A): N = len (A) A = [ 1 ] + A + [ 1 ] # Add Bordering Balloons dp = [[ 0 for x in range (N + 2 )] for y in range (N + 2 )] # Declare DP Array for length in range ( 1 , N + 1 ): for left in range ( 1 , N - length + 2 ): right = left + length - 1 # For a sub-array from indices left, right # This innermost loop finds the last balloon burst for last in range (left, right + 1 ): dp[left][right] = max (dp[left][right], \ dp[left][last - 1 ] + \ A[left - 1 ] * A[last] * A[right + 1 ] + \ dp[last + 1 ][right]) return (dp[ 1 ][N]) # Driver code A = [ 1 , 2 , 3 , 4 , 5 ] print (getMax(A)) |
C#
// C# program to illustrate // Burst balloon problem using System; class GFG{ public static int getMax( int [] A, int N) { // Add Bordering Balloons int [] B = new int [N + 2]; B[0] = B[N + 1] = 1; for ( int i = 1; i <= N; i++) B[i] = A[i - 1]; // Declaring DP array int [,] dp = new int [(N + 2), (N + 2)]; for ( int length = 1; length < N + 1; length++) { for ( int left = 1; left < N - length + 2; left++) { int right = left + length -1; // For a sub-array from indices // left, right. This innermost // loop finds the last balloon burst for ( int last = left; last < right + 1; last++) { dp[left, right] = Math.Max( dp[left, right], dp[left, last - 1] + B[left - 1] * B[last] * B[right + 1] + dp[last + 1, right]); } } } return dp[1, N]; } // Driver code public static void Main() { int [] A = new int [] { 1, 2, 3, 4, 5 }; // Size of the array int N = A.Length; // Calling function Console.WriteLine(getMax(A, N)); } } // This code is contributed by sanjoy_62 |
Javascript
<script> // Javascript program burst balloon problem function getMax(A, N) { // Add Bordering Balloons var B = new Array(N+2); B[0] = 1; B[N + 1] = 1; for ( var i = 1; i <= N; i++) B[i] = A[i - 1]; // Declare DP Array var dp = new Array(N + 2); for ( var i = 0; i < dp.length; i++) { dp[i] = new Array(N + 2).fill(0); } for ( var length = 1; length < N + 1; length++) { for ( var left = 1; left < N - length + 2; left++) { var right = left + length - 1; // For a sub-array from indices left, right // This innermost loop finds the last balloon burst for ( var last = left; last < right + 1; last++) { dp[left][right] = Math.max(dp[left][right], dp[left][last - 1] + B[left - 1] * B[last] * B[right + 1] + dp[last + 1][right]); } } } return dp[1][N]; } // Driver code var A = [ 1, 2, 3, 4, 5 ]; // Size of the array var N = A.length; // Calling function document.write(getMax(A, N)); // This code is contributed by shubhamsingh10 </script> |
110
Time Complexity: O(N3)
Auxiliary Space: O(N2)
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