Merge pull request #228 from shafa45/main

problems on strings

Author: gantavyamalviya

String/KMPalgo.cpp

@@ -0,0 +1,69 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+void fillLPS(string s, int lps[])
+{
+    int n = s.length();
+    int len = 0;
+    int i = 1;
+    lps[0] = 0;
+    while (i < n)
+    {
+        if (s[i] == s[len])
+        {
+            len++;
+            lps[i] = len;
+            i++;
+        }
+        else
+        {
+            if (len == 0)
+            {
+                lps[i] = 0;
+                i++;
+            }
+            else
+            {
+                len = lps[len - 1];
+            }
+        }
+    }
+}
+
+void KMP(string txt, string pat)
+{
+    int n = txt.length();
+    int m = pat.length();
+    int lps[m];
+    fillLPS(pat, lps);
+
+    int i = 0, j = 0;
+    while (i < n)
+    {
+        if (txt[i] == pat[j])
+        {
+            i++;
+            j++;
+        }
+        if (j == m)
+        {
+            cout << (i - m) << " ";
+            j = lps[j - 1];
+        }
+        else if (i < n && txt[i] != pat[j])
+        {
+            if (j == 0)
+                i++;
+            else
+                j = lps[j - 1];
+        }
+    }
+}
+
+int main()
+{
+    string txt, pat;
+    cin >> txt >> pat;
+    KMP(txt, pat);
+    return 0;
+}

String/angramSearch.cpp

@@ -0,0 +1,45 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+const int CHAR = 256;
+
+bool isSame(int a[], int b[])
+{
+    for (int i = 0; i < CHAR; i++)
+    {
+        if (a[i] != b[i])
+            return false;
+    }
+    return true;
+}
+
+bool anagramSeach(string txt, string pat)
+{
+    int n = txt.length();
+    int m = pat.length();
+    int ct[CHAR] = {0};
+    int cp[CHAR] = {0};
+    for (int i = 0; i < m; i++)
+    {
+        ct[txt[i]]++;
+        cp[pat[i]]++;
+    }
+    if (m == n)
+        return isSame(ct, cp);
+    for (int i = m; i < n; i++)
+    {
+        if (isSame(ct, cp))
+            return true;
+        ct[txt[i]]++;
+        ct[txt[i - m]]--;
+    }
+    return false;
+}
+
+int main()
+{
+    string s, k;
+    cin >> s >> k;
+    cout << anagramSeach(s, k);
+    return 0;
+}

String/areRotation.cpp

@@ -0,0 +1,17 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+bool areRotated(string s1, string s2)
+{
+    if (s1.length() != s2.length())
+        return false;
+    return (s1 + s1).find(s2) != string::npos;
+}
+
+int main()
+{
+    string s1, s2;
+    cin >> s1 >> s2;
+    cout << areRotated(s1, s2);
+    return 0;
+}