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Find the maximum cost path from the bottom-left corner to the top-right corner

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Given a two dimensional grid, each cell of which contains integer cost which represents a cost to traverse through that cell. The task is to find the maximum cost path from the bottom-left corner to the top-right corner.
Note: Use up and right moves only 

Examples: 

Input : mat[][] = {{20, -10, 0}, 
                   {1, 5, 10}, 
                   {1, 2, 3}}
Output : 18
(2, 0) ==> (2, 1) ==> (1, 1) ==> (1, 2) ==> (0, 2)  
cost for this path is (1+2+5+10+0) = 18

Input : mat[][] = {{1, -2, -3}, 
                   {1, 15, 10},
                   {1, -2, 3}}
Output : 24

Prerequisites: Minimum Cost Path with Left, Right, Bottom and Up moves allowed 
Approach: The idea is to maintain a separate array to store the maximum cost for all the cells using queue. For every cell check if current cost in reaching that cell is more than the previous cost or not. If previous cost is minimum then update the cell with the current cost.

Below is the implementation of the above approach :  

C++




// C++ program to find maximum cost to reach
// top right corner from bottom left corner
#include <bits/stdc++.h>
using namespace std;
 
#define ROW 3
#define COL 3
 
// To store matrix cell coordinates
struct Point
{
    int x;
    int y;
};
 
// Check whether given cell (row, col)
// is a valid cell or not.
bool isValid(Point p)
{
    // Return true if row number and column number
    // is in range
    return (p.x >=0) && (p.y <COL);
}
 
 
// Function to find maximum cost to reach
// top right corner from bottom left corner
int find_max_cost(int mat[][COL])
{
    int max_val[ROW][COL];
    memset(max_val, 0, sizeof max_val);
        max_val[ROW-1][0] = mat[ROW-1][0];
     
    // Starting point   
    Point src = {ROW-1,0};
 
    // Create a queue for traversal
    queue<Point> q;
     
    q.push(src); // Enqueue source cell
 
    // Do a BFS starting from source cell
    // on the allowed direction
    while (!q.empty())
    {
        Point curr = q.front();
        q.pop();
     
        // Find up point
        Point up = {curr.x-1, curr.y};
             
        // if adjacent cell is valid, enqueue it.
        if (isValid(up))
        {
            max_val[up.x][up.y] = max(max_val[up.x][up.y],
                 mat[up.x][up.y] + max_val[curr.x][curr.y]);
            q.push(up);
        }
         
        // Find right point   
        Point right = {curr.x, curr.y+1};
     
        if(isValid(right))
        {
            max_val[right.x][right.y] = max(max_val[right.x][right.y],
                mat[right.x][right.y] + max_val[curr.x][curr.y]);
            q.push(right);
        }
         
    }
     
    // Return the required answer
    return max_val[0][COL-1];
}
 
// Driver code
int main()
{
    int mat[ROW][COL] = { {20, -10, 0},
                          {1, 5, 10},
                          {1, 2, 3},};
 
    std::cout<<"Given matrix is "<<endl;
 
    for(int i = 0 ; i<ROW;++i)
    {
        for(int j =0; j<COL; ++j)
            std::cout<<mat[i][j]<<" ";
 
        std::cout<<endl;
    }
     
    std::cout<<"Maximum cost is " << find_max_cost(mat);
 
    return 0;
}


Java




// Java program to find maximum cost to reach
// top right corner from bottom left corner
import java.util.*;
class GFG
{
static int ROW = 3;
static int COL = 3;
 
// To store matrix cell coordinates
static class Point
{
    int x;
    int y;
 
    public Point(int x, int y)
    {
        this.x = x;
        this.y = y;
    }
}
 
// Check whether given cell (row, col)
// is a valid cell or not.
static boolean isValid(Point p)
{
    // Return true if row number and column number
    // is in range
    return (p.x >= 0) && (p.y < COL);
}
 
// Function to find maximum cost to reach
// top right corner from bottom left corner
static int find_max_cost(int mat[][])
{
    int [][]max_val = new int[ROW][COL];
    max_val[ROW - 1][0] = mat[ROW - 1][0];
     
    // Starting point
    Point src = new Point(ROW - 1, 0);
 
    // Create a queue for traversal
    Queue<Point> q = new LinkedList<>();
     
    q.add(src); // Enqueue source cell
 
    // Do a BFS starting from source cell
    // on the allowed direction
    while (!q.isEmpty())
    {
        Point curr = q.peek();
        q.remove();
     
        // Find up point
        Point up = new Point(curr.x - 1, curr.y);
             
        // if adjacent cell is valid, enqueue it.
        if (isValid(up))
        {
            max_val[up.x][up.y] = Math.max(max_val[up.x][up.y],
                mat[up.x][up.y] + max_val[curr.x][curr.y]);
            q.add(up);
        }
         
        // Find right point
        Point right = new Point(curr.x, curr.y + 1);
     
        if(isValid(right))
        {
            max_val[right.x][right.y] = Math.max(max_val[right.x][right.y],
                mat[right.x][right.y] + max_val[curr.x][curr.y]);
            q.add(right);
        }
    }
     
    // Return the required answer
    return max_val[0][COL - 1];
}
 
// Driver code
public static void main(String[] args)
{
    int mat[][] = {{20, -10, 0},
                   {1, 5, 10},
                   {1, 2, 3}};
 
    System.out.println("Given matrix is ");
 
    for(int i = 0 ; i < ROW; ++i)
    {
        for(int j = 0; j < COL; ++j)
            System.out.print(mat[i][j] + " ");
 
        System.out.println();
    }
     
    System.out.print("Maximum cost is " +
                     find_max_cost(mat));
}
}
 
// This code is contributed by PrinciRaj1992


Python3




# Python3 program to find maximum cost to reach
# top right corner from bottom left corner
from collections import deque as queue
 
ROW = 3
COL = 3
 
# Check whether given cell (row, col)
# is a valid cell or not.
def isValid(p):
     
    # Return true if row number and column number
    # is in range
    return (p[0] >= 0) and (p[1] < COL)
 
# Function to find maximum cost to reach
# top right corner from bottom left corner
def find_max_cost(mat):
    max_val = [[0 for i in range(COL)] for i in range(ROW)]
 
    max_val[ROW - 1][0] = mat[ROW - 1][0]
 
    # Starting po
    src = [ROW - 1, 0]
 
    # Create a queue for traversal
    q = queue()
 
    q.appendleft(src) # Enqueue source cell
 
    # Do a BFS starting from source cell
    # on the allowed direction
    while (len(q) > 0):
        curr = q.pop()
 
        # Find up point
        up = [curr[0] - 1, curr[1]]
 
        # if adjacent cell is valid, enqueue it.
        if (isValid(up)):
            max_val[up[0]][up[1]] = max(max_val[up[0]][up[1]],mat[up[0]][up[1]] + max_val[curr[0]][curr[1]])
            q.appendleft(up)
 
 
        # Find right po
        right = [curr[0], curr[1] + 1]
 
        if(isValid(right)):
            max_val[right[0]][right[1]] = max(max_val[right[0]][right[1]],mat[right[0]][right[1]] + max_val[curr[0]][curr[1]])
            q.appendleft(right)
 
 
    # Return the required answer
    return max_val[0][COL - 1]
 
# Driver code
mat = [[20, -10, 0],
    [1, 5, 10],
    [1, 2, 3]]
 
print("Given matrix is ")
 
for i in range(ROW):
    for j in range(COL):
        print(mat[i][j],end=" ")
    print()
 
print("Maximum cost is ", find_max_cost(mat))
 
# This code is contributed by mohit kumar 29


C#




// C# program to find maximum cost to reach
// top right corner from bottom left corner
using System;
using System.Collections.Generic;
 
class GFG
{
     
static int ROW = 3;
static int COL = 3;
 
// To store matrix cell coordinates
public class Point
{
    public int x;
    public int y;
 
    public Point(int x, int y)
    {
        this.x = x;
        this.y = y;
    }
}
 
// Check whether given cell (row, col)
// is a valid cell or not.
static Boolean isValid(Point p)
{
    // Return true if row number and
    // column number is in range
    return (p.x >= 0) && (p.y < COL);
}
 
// Function to find maximum cost to reach
// top right corner from bottom left corner
static int find_max_cost(int [,]mat)
{
    int [,]max_val = new int[ROW,COL];
    max_val[ROW - 1, 0] = mat[ROW - 1, 0];
      
    // Starting point
    Point src = new Point(ROW - 1, 0);
 
    // Create a queue for traversal
    Queue<Point> q = new Queue<Point>();
     
    q.Enqueue(src); // Enqueue source cell
 
    // Do a BFS starting from source cell
    // on the allowed direction
    while (q.Count != 0)
    {
        Point curr = q.Peek();
        q.Dequeue();
     
        // Find up point
        Point up = new Point(curr.x - 1, curr.y);
             
        // if adjacent cell is valid, enqueue it.
        if (isValid(up))
        {
            max_val[up.x, up.y] = Math.Max(max_val[up.x, up.y],
                mat[up.x, up.y] + max_val[curr.x, curr.y]);
            q.Enqueue(up);
        }
         
        // Find right point
        Point right = new Point(curr.x,
                                curr.y + 1);
     
        if(isValid(right))
        {
            max_val[right.x, right.y] = Math.Max(max_val[right.x, right.y],
                mat[right.x, right.y] + max_val[curr.x, curr.y]);
            q.Enqueue(right);
        }
    }
     
    // Return the required answer
    return max_val[0, COL - 1];
}
 
// Driver code
public static void Main(String[] args)
{
    int [,]mat = {{20, -10, 0},
                  {1, 5, 10},
                  {1, 2, 3}};
 
    Console.WriteLine("Given matrix is ");
 
    for(int i = 0 ; i < ROW; ++i)
    {
        for(int j = 0; j < COL; ++j)
            Console.Write(mat[i, j] + " ");
 
        Console.WriteLine();
    }
     
    Console.Write("Maximum cost is " +
                  find_max_cost(mat));
}
}
 
// This code is contributed by Princi Singh


Javascript




<script>
 
// Javascript program to find maximum cost to reach
// top right corner from bottom left corner
let ROW = 3;
let COL = 3;
 
// To store matrix cell coordinates
class Point
{
    constructor(x, y)
    {
        this.x = x;
        this.y = y;
    }
}
 
// Check whether given cell (row, col)
// is a valid cell or not.
function isValid(p)
{
     
    // Return true if row number and column
    // number is in range
    return (p.x >= 0) && (p.y < COL);
}
 
// Function to find maximum cost to reach
// top right corner from bottom left corner
function find_max_cost(mat)
{
    let max_val = new Array(ROW);
    for(let i = 0; i < ROW; i++)
    {
        max_val[i] = new Array(COL);
        for(let j = 0; j < COL; j++)
        {
            max_val[i][j] = 0;
        }
    }
    max_val[ROW - 1][0] = mat[ROW - 1][0];
       
    // Starting point
    let src = new Point(ROW - 1, 0);
   
    // Create a queue for traversal
    let q = [];
     
    // Enqueue source cell
    q.push(src);
   
    // Do a BFS starting from source cell
    // on the allowed direction
    while (q.length != 0)
    {
        let curr = q.shift();
         
        // Find up point
        let up = new Point(curr.x - 1, curr.y);
               
        // If adjacent cell is valid, enqueue it.
        if (isValid(up))
        {
            max_val[up.x][up.y] = Math.max(max_val[up.x][up.y],
                mat[up.x][up.y] + max_val[curr.x][curr.y]);
            q.push(up);
        }
           
        // Find right point
        let right = new Point(curr.x, curr.y + 1);
       
        if(isValid(right))
        {
            max_val[right.x][right.y] = Math.max(max_val[right.x][right.y],
                mat[right.x][right.y] + max_val[curr.x][curr.y]);
            q.push(right);
        }
    }
       
    // Return the required answer
    return max_val[0][COL - 1];
}
 
// Driver code
let mat = [ [ 20, -10, 0 ],
            [ 1, 5, 10 ],
            [ 1, 2, 3 ] ];
   
document.write("Given matrix is <br>");
 
for(let i = 0; i < ROW; ++i)
{
    for(let j = 0; j < COL; ++j)
        document.write(mat[i][j] + " ");
 
    document.write("<br>");
}
   
document.write("Maximum cost is " +
               find_max_cost(mat));
 
// This code is contributed by patel2127
 
</script>


Output: 

Given matrix is 
20 -10 0 
1 5 10 
1 2 3 
Maximum cost is 18

 

Time Complexity: O(ROW * COL)
Auxiliary Space: O(ROW * COL)



Last Updated : 17 Dec, 2021
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