[ADD] Longest Palindrome String

longest/longest_palindrome_string.cpp

@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <string.h>
+
+void printSubStr(char *str, int low, int high)
+{
+    for (int i = low; i <= high; ++i)
+        printf("%c", str[i]);
+}
+
+int longestPalSubstr(char *str)
+{
+    int n = strlen(str); 
+    bool table[n][n];
+    memset(table, 0, sizeof(table));
+
+    int maxLength = 1;
+    for (int i = 0; i < n; ++i)
+        table[i][i] = true;
+
+    int start = 0;
+    for (int i = 0; i < n - 1; ++i)
+    {
+        if (str[i] == str[i + 1])
+        {
+            table[i][i + 1] = true;
+            start = i;
+            maxLength = 2;
+        }
+    }
+
+    for (int k = 3; k <= n; ++k)
+    {
+        for (int i = 0; i < n - k + 1; ++i)
+        {
+
+            int j = i + k - 1;
+
+            if (table[i + 1][j - 1] && str[i] == str[j])
+            {
+                table[i][j] = true;
+
+                if (k > maxLength)
+                {
+                    start = i;
+                    maxLength = k;
+                }
+            }
+        }
+    }
+
+    printf("Longest palindrome substring is: ");
+    printSubStr(str, start, start + maxLength - 1);
+
+    return maxLength; 
+}
+
+int main()
+{
+    char str[] = ""; 
+    printf("\nLength is: %d\n", longestPalSubstr(str));
+    return 0;
+}