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Daily Coding Challenge #25

wingkwong profile image Wing-Kam ・2 min read

About

This is a series of Daily Coding Challenge. Each day I show a few solutions written in C++. The questions are from coding practice/contest sites such as HackerRank, LeetCode, Codeforces, Atcoder and etc.


Bot saves princess

Princess Peach is trapped in one of the four corners of a square grid. You are in the center of the grid and can move one step at a time in any of the four directions. Can you rescue the princess?

Input format

The first line contains an odd integer N (3 <= N < 100) denoting the size of the grid. This is followed by an NxN grid. Each cell is denoted by '-' (ascii value: 45). The bot position is denoted by 'm' and the princess position is denoted by 'p'.

Grid is indexed using Matrix Convention

Output format

Print out the moves you will take to rescue the princess in one go. The moves must be separated by '\n', a newline. The valid moves are LEFT or RIGHT or UP or DOWN.

Sample input

3
---
-m-
p--

Sample output

DOWN
LEFT

Task

Complete the function displayPathtoPrincess which takes in two parameters - the integer N and the character array grid. The grid will be formatted exactly as you see it in the input, so for the sample input the princess is at grid[2][0]. The function shall output moves (LEFT, RIGHT, UP or DOWN) on consecutive lines to rescue/reach the princess. The goal is to reach the princess in as few moves as possible.

The above sample input is just to help you understand the format. The princess ('p') can be in any one of the four corners.

Scoring
Your score is calculated as follows : (NxN - number of moves made to rescue the princess)/10, where N is the size of the grid (3x3 in the sample testcase).

Approach

Given the fact that the princess is located in the corner and you are in the center, it simply finds out which directions to move. We only need to move n/2 times to rescue the princess.

#include <iostream>
#include <vector>
using namespace std;

void displayPathtoPrincess(int n, vector <string> grid){
    string h,v;

    // top-left
    if(grid[0][0]=='p'){
        h="LEFT";
    }
    // top-right
    else if(grid[0][n-1]=='p'){
        v="UP"; h="RIGHT";
    }
    // bottom-left
    else if(grid[n-1][0]=='p') {
        v="DOWN"; h="LEFT";
    }
    // bottom-right
    else if(grid[n-1][n-1]=='p'){
         v="DOWN"; h="RIGHT";
    }

    for(int i=0;i<n/2;i++) cout << v << "\n";
    for(int i=0;i<n/2;i++) cout << h << "\n";
}

int main(void) {

    int m;
    vector <string> grid;

    cin >> m;

    for(int i=0; i<m; i++) {
        string s; cin >> s;
        grid.push_back(s);
    }

    displayPathtoPrincess(m,grid);

    return 0;
}

The source code is available in corresponding repo below. Star and watch for timely updates!

GitHub logo wingkwong / leetcode

🏆 A Collection of my LeetCode Solutions with Explanations 🏆

GitHub logo wingkwong / hackerrank

🏆 A Collection of my HackerRank Solutions with Explanations 🏆

GitHub logo wingkwong / codeforces

🏆 A Collection of my Codeforces Solutions with Explanations 🏆

GitHub logo wingkwong / atcoder

🏆 A Collection of my AtCoder Solutions with Explanations 🏆

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Wing-Kam

@wingkwong

Consultant by day. Developer by night. AWS certified. Exploring #CloudNative currently.

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