Dadas dos strings s1 y s2, encuentre si s1 es una substring de s2. En caso afirmativo, devuelve el índice de la primera aparición, de lo contrario, devuelve -1.
Ejemplos:
C++
// C++ program to check if a string is
// substring of other.
#include <bits/stdc++.h>
using namespace std;
// Returns true if s1 is substring of s2
int isSubstring(string s1, string s2)
{
int M = s1.length();
int N = s2.length();
/* A loop to slide pat[] one by one */
for (int i = 0; i <= N - M; i++) {
int j;
/* For current index i, check for
pattern match */
for (j = 0; j < M; j++)
if (s2[i + j] != s1[j])
break;
if (j == M)
return i;
}
return -1;
}
/* Driver code */
int main()
{
string s1 = "for";
string s2 = "geeksforgeeks";
int res = isSubstring(s1, s2);
if (res == -1)
cout << "Not present";
else
cout << "Present at index " << res;
return 0;
}
Java
// Java program to check if a string is
// substring of other.
class GFG {
// Returns true if s1 is substring of s2
static int isSubstring(
String s1, String s2)
{
int M = s1.length();
int N = s2.length();
/* A loop to slide pat[] one by one */
for (int i = 0; i <= N - M; i++) {
int j;
/* For current index i, check for
pattern match */
for (j = 0; j < M; j++)
if (s2.charAt(i + j)
!= s1.charAt(j))
break;
if (j == M)
return i;
}
return -1;
}
/* Driver code */
public static void main(String args[])
{
String s1 = "for";
String s2 = "geeksforgeeks";
int res = isSubstring(s1, s2);
if (res == -1)
System.out.println("Not present");
else
System.out.println(
"Present at index "
+ res);
}
}
// This code is contributed by JaideepPyne.
Python3
# Python3 program to check if
# a string is substring of other.
# Returns true if s1 is substring of s2
def isSubstring(s1, s2):
M = len(s1)
N = len(s2)
# A loop to slide pat[] one by one
for i in range(N - M + 1):
# For current index i,
# check for pattern match
for j in range(M):
if (s2[i + j] != s1[j]):
break
if j + 1 == M :
return i
return -1
# Driver Code
if __name__ == "__main__":
s1 = "for"
s2 = "geeksforgeeks"
res = isSubstring(s1, s2)
if res == -1 :
print("Not present")
else:
print("Present at index " + str(res))
# This code is contributed by ChitraNayal
C#
// C# program to check if a string is
// substring of other.
using System;
class GFG {
// Returns true if s1 is substring of s2
static int isSubstring(string s1, string s2)
{
int M = s1.Length;
int N = s2.Length;
/* A loop to slide pat[] one by one */
for (int i = 0; i <= N - M; i++) {
int j;
/* For current index i, check for
pattern match */
for (j = 0; j < M; j++)
if (s2[i + j] != s1[j])
break;
if (j == M)
return i;
}
return -1;
}
/* Driver code */
public static void Main()
{
string s1 = "for";
string s2 = "geeksforgeeks";
int res = isSubstring(s1, s2);
if (res == -1)
Console.Write("Not present");
else
Console.Write("Present at index "
+ res);
}
}
// This code is contributed by nitin mittal.
PHP
<?php
// PHP program to check if a
// string is substring of other.
// Returns true if s1 is substring of s2
function isSubstring($s1, $s2)
{
$M = strlen($s1);
$N = strlen($s2);
// A loop to slide
// pat[] one by one
for ($i = 0; $i <= $N - $M; $i++)
{
$j = 0;
// For current index i,
// check for pattern match
for (; $j < $M; $j++)
if ($s2[$i + $j] != $s1[$j])
break;
if ($j == $M)
return $i;
}
return -1;
}
// Driver Code
$s1 = "for";
$s2 = "geeksforgeeks";
$res = isSubstring($s1, $s2);
if ($res == -1)
echo "Not present";
else
echo "Present at index " . $res;
// This code is contributed by mits
?>
Javascript
<script>
// JavaScript program to check if a string is
// substring of other.
// Returns true if s1 is substring of s2
function isSubstring(s1, s2)
{
var M = s1.length;
var N = s2.length;
/* A loop to slide pat[] one by one */
for (var i = 0; i <= N - M; i++) {
var j;
/* For current index i, check for
pattern match */
for (j = 0; j < M; j++)
if (s2[i + j] != s1[j])
break;
if (j == M)
return i;
}
return -1;
}
/* Driver code */
var s1 = "for";
var s2 = "geeksforgeeks";
var res = isSubstring(s1, s2);
if (res == -1)
document.write( "Not present");
else
document.write( "Present at index " + res);
</script>
C++
#include <bits/stdc++.h>
using namespace std;
int Substr(string s2, string s1)
{
int counter = 0; // pointing s2
int i = 0;
for(;i<s1.length();i++)
{
if(counter==s2.length())
break;
if(s2[counter]==s1[i])
{
counter++;
}
else
{
// Special case where character preceding the i'th character is duplicate
if(counter > 0)
{
i -= counter;
}
counter = 0;
}
}
return counter < s2.length()?-1:i-counter;
}
// Driver code
int main()
{
string s1 = "geeksforgeeks";
cout << Substr("for", s1);
return 0;
}
// this code is contributed by Manu Pathria
Java
import java.io.*;
class GFG {
public static int Substr(String s2, String s1){
int counter = 0; //pointing s2
int i = 0;
for(;i<s1.length();i++){
if(counter==s2.length())
break;
if(s2.charAt(counter)==s1.charAt(i)){
counter++;
}else{
//Special case where character preceding the i'th character is duplicate
if(counter>0){
i -= counter;
}
counter = 0;
}
}
return counter < s2.length()?-1:i-counter;
}
public static void main (String[] args) {
String s1 = "geeksforgeeks";
//System.out.println(s2.indexOf("for"));
System.out.println(Substr("for", s1));
}
}
Python3
# Python program for the above approach
def Substr(s1, s2):
counter = 0
i = 0
Len = len(s1)
while(i < Len):
if(counter == len(s2)):
break;
if(s2[counter] == s1[i]):
counter += 1
else:
if(counter > 0):
i -= counter
counter = 0
i += 1
if (counter < len(s2)):
return -1
else:
return (i - counter)
# Driver code
print(Substr("geeksforgeeks", "for"))
# This code is contributed by avanitrachhadiya2155
C#
// C# program for the above approach
using System;
class GFG {
static int Substr(string s2, string s1)
{
int counter = 0; // pointing s2
int i = 0;
for (; i < s1.Length; i++) {
if (counter == s2.Length)
break;
if (s2[counter] == s1[i]) {
counter++;
}
else {
// Special case where character preceding
// the i'th character is duplicate
if (counter > 0) {
i -= counter;
}
counter = 0;
}
}
return counter < s2.Length ? -1 : i - counter;
}
// Driver code
public static int Main()
{
string s1 = "geeksforgeeks";
Console.Write(Substr("for", s1));
return 0;
}
}
// This code is contributed by Taranpreet
Javascript
<!-- Javascript program for the above approach -->
<script>
function Substr( s2, s1){
var counter = 0; // pointing s2
var i = 0;
for( ;i < s1.length; i++)
{
if( counter == s2.length )
{
break;
}
if( s2[counter] == s1[i] )
{
counter++;
}
else
{
// Special case where character preceding
// the i'th character is duplicate
if(counter > 0)
{
i -= counter;
}
counter = 0;
}
}
return counter < s2.length ? -1 : i-counter;
}
// Driver code
var s1 = "geeksforgeeks";
document.write(Substr("for", s1));
</script>
<!-- this code is contributed by Nirajgusain5 -->
C++
//C++ implementation of the approach
#include <bits/stdc++.h>
using namespace std;
// function to get the index of s2 in s1
int isSubstring(string s1, string s2)
{
// using find method to check if s1 is
// a substring of s2
if (s2.find(s1) != string::npos)
return s2.find(s1);
return -1;
}
// Driver code
int main()
{
string s1 = "for";
string s2 = "geeksforgeeks";
//Function Call
int res = isSubstring(s1, s2);
if (res == -1)
cout << "Not present";
else
cout << "Present at index " << res;
return 0;
}
// this code is contributed by phasing17
Python3
# Python3 program to check if
# a string is substring of other.
# Checks if s1 is a substring of s2
def isSubstring(s1, s2):
if s1 in s2:
return s2.index(s1)
return -1
# Driver Code
if __name__ == "__main__":
s1 = "for"
s2 = "geeksforgeeks"
res = isSubstring(s1, s2)
if res == -1 :
print("Not present")
else:
print("Present at index " + str(res))
# This code is contributed by phasing17
Java
//Java program to implement the approach
class GFG {
// function to get the index of s2 in s1
static int isSubstring(String s1, String s2)
{
// using indexOf method to check if s1 is
// a substring of s2
return s2.indexOf(s1);
}
public static void main(String[] args) {
String s1 = "for";
String s2 = "geeksforgeeks";
//Function Call
int res = isSubstring(s1, s2);
if (res == -1)
System.out.println("Not present");
else
System.out.println("Present at index " + res);
}
}
//this code is contributed by phasing17
Javascript
//JS program to implement the approach
// function to get the index of s2 in s1
function isSubstring(s1, s2)
{
// using indexOf method to check if s1 is
// a substring of s2
return s2.indexOf(s1);
}
// Driver code
var s1 = "for";
var s2 = "geeksforgeeks";
//Function Call
var res = isSubstring(s1, s2);
if (res == -1)
console.log("Not present");
else
console.log("Present at index " + res);
// this code is contributed by phasing17
C#
// C# program to implement the approach
using System;
public class GFG {
// function to get the index of s2 in s1
static int isSubstring(string s1, string s2)
{
// using IndexOf method to check if s1 is
// a substring of s2
return s2.IndexOf(s1);
}
public static void Main(string[] args)
{
string s1 = "for";
string s2 = "geeksforgeeks";
// Function Call
int res = isSubstring(s1, s2);
if (res == -1)
Console.WriteLine("Not present");
else
Console.WriteLine("Present at index " + res);
}
}
// this code is contributed by phasing17