Given a string str of size N containing two types of character only that are “I” or “D”. The task is to generate an array arr[0, 1, . . N] of size N + 1 satisfying the following conditions:
- If str[i] == “I” then arr[i] < arr[i+1]
- If str[i] == “D” then arr[i] > arr[i+1]
Examples:
Input: str = “IDID”
Output: 0 4 1 3 2
Explanation:
str[0] == “I” therefore arr[0] < arr[1]
str[1] == “D” therefore arr[1] > arr[2]
str[2] == “I” therefore arr[2] < arr[3]
str[3] == “D” therefore arr[3] > arr[4]Input: str = “III”
Output: 0 1 2 3
Approach:
- Initialize variable START as 0 and END as N.
- Iterate over the entire array.
- If str[i] == “I” then assign START at arr[i] and Increment the START.
- If str[i] == “D” then assign END at arr[i] and Decrement the END.
- Now the last element of the array isn’t assigned so assign START at A[N].
Below is the implementation of the approach.
C++
// C++ program to Generate an increasing// and decreasing array#include <iostream>using namespace std;// Function that returns generated arrayint* DiStirngMatch(string Str){ int N = Str.length(); // Dynamically allocate array int* arr = new int[N]; // START=0, END=N int START = 0, END = N; // iterate over array for (int i = 0; i < N; i++) { // if Str[i]=='I' assign arr[i] // as START and increment START if (Str[i] == 'I') arr[i] = START++; // if str[i]=='D' assign arr[i] // as END and decrement END if (Str[i] == 'D') arr[i] = END--; } // assign A[N] as START arr[N] = START; // return starting // address of array A return arr;}// Driver Programint main(){ string Str = "IDID"; int N = Str.length(); int* ptr = DiStirngMatch(Str); for (int i = 0; i <= N; i++) cout << ptr[i] << " "; return 0;} |
Java
// Java program to generate an increasing// and decreasing arrayclass GFG{// Function that returns generated arraystatic int []DiStirngMatch(String Str){ int N = Str.length(); // Dynamically allocate array int []arr = new int[N + 1]; // START=0, END=N int START = 0, END = N; // Iterate over array for(int i = 0; i < N; i++) { // if Str[i]=='I' assign arr[i] // as START and increment START if (Str.charAt(i) == 'I') arr[i] = START++; // if str[i]=='D' assign arr[i] // as END and decrement END if (Str.charAt(i) == 'D') arr[i] = END--; } // Assign A[N] as START arr[N] = START; // Return starting // address of array A return arr;}// Driver codepublic static void main(String[] args){ String Str = "IDID"; int N = Str.length(); int[] ptr = DiStirngMatch(Str); for(int i = 0; i <= N; i++) System.out.print(ptr[i] + " ");}}// This code is contributed by amal kumar choubey |
Python3
# Python3 program to generate an # increasing and decreasing array# Function that returns generated arraydef DiStirngMatch(Str): N = len(Str) # Dynamically allocate array arr = (N + 1) * [0] # START, END= 0 ,N START, END = 0, N # Iterate over array for i in range (N): # If Str[i]=='I' assign arr[i] # as START and increment START if (Str[i] == 'I'): arr[i] = START START += 1 # If str[i]=='D' assign arr[i] # as END and decrement END if (Str[i] == 'D'): arr[i] = END END -= 1 # Assign A[N] as START arr[N] = START # Return starting # address of array A return arr# Driver codeif __name__ == "__main__": Str = "IDID" N = len(Str) ptr = DiStirngMatch(Str) for i in range (N + 1): print(ptr[i], end = " ")# This code is contributed by chitranayal |
C#
// C# program to generate an increasing// and decreasing arrayusing System;class GFG{// Function that returns generated arraystatic int []DiStirngMatch(String Str){ int N = Str.Length; // Dynamically allocate array int []arr = new int[N + 1]; // START=0, END=N int START = 0, END = N; // Iterate over array for(int i = 0; i < N; i++) { // if Str[i]=='I' assign arr[i] // as START and increment START if (Str[i] == 'I') arr[i] = START++; // if str[i]=='D' assign arr[i] // as END and decrement END if (Str[i] == 'D') arr[i] = END--; } // Assign A[N] as START arr[N] = START; // Return starting // address of array A return arr;}// Driver codepublic static void Main(String[] args){ String Str = "IDID"; int N = Str.Length; int[] ptr = DiStirngMatch(Str); for(int i = 0; i <= N; i++) Console.Write(ptr[i] + " ");}}// This code is contributed by amal kumar choubey |
Javascript
<script>// Javascript program to Generate an increasing// and decreasing array// Function that returns generated arrayfunction DiStirngMatch( Str){ var N = Str.length; // Dynamically allocate array var arr = Array(N).fill(0); // START=0, END=N var START = 0, END = N; // iterate over array for (var i = 0; i < N; i++) { // if Str[i]=='I' assign arr[i] // as START and increment START if (Str[i] == 'I') arr[i] = START++; // if str[i]=='D' assign arr[i] // as END and decrement END if (Str[i] == 'D') arr[i] = END--; } // assign A[N] as START arr[N] = START; // return starting // address of array A return arr;}// Driver Programvar Str = "IDID";var N = Str.length;var ptr = DiStirngMatch(Str);for (var i = 0; i <= N; i++) document.write( ptr[i] + " ");// This code is contributed by itsok.</script> |
Output:
0 4 1 3 2
Time Complexity: O (N)
Auxiliary Space: O (N)
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