Added 1 solution & modified 2 solutions

varunu28 · varunu28 · commit fdc165517469 · 2020-03-08T09:19:56.000-07:00
diff --git a/Easy/Confusing Number.java b/Easy/Confusing Number.java
@@ -1,25 +1,20 @@
 class Solution {
-    public boolean confusingNumber(int N) {
-        if (N == 0) {
-            return false;
-        }
-        int copy = N;
-        StringBuilder sb = new StringBuilder();
-        while (N > 0) {
-            int temp = N % 10;
-            if (temp == 6 || temp == 9) {
-                sb.append(temp == 6 ? 9 : 6); 
-            }
-            else if (temp == 0 || temp == 1 || temp == 8) {
-                sb.append(temp);
-            }
-            else {
-                return false;
-            }
-            
-            N /= 10;
-        }
-        
-        return Integer.parseInt(sb.toString()) != copy;
+  public boolean confusingNumber(int N) {
+    int newNum = 0;
+    int copy = N;
+    while (N > 0) {
+      int rem = N % 10;
+      N /= 10;
+      if (rem == 0 || rem == 1 || rem == 8) {
+        newNum = newNum * 10 + rem;
+      }
+      else if (rem == 6 || rem == 9) {
+        newNum = newNum * 10 + (rem == 6 ? 9 : 6);
+      }
+      else {
+        return false;
+      }
     }
+    return newNum != copy;
+  }
 }
diff --git a/Easy/Find the difference.java b/Easy/Find the difference.java
@@ -1,25 +1,15 @@
-public class Solution {
-    public char findTheDifference(String s, String t) {
-        String s1 = s;
-        String s2 = t;
-        s1 = sortString(s1);
-        s2 = sortString(s2);
-
-        char ans = '0';
-
-        for (int i=0;i< s1.length();i++) {
-            if (s2.charAt(i) != s1.charAt(i)) {
-                ans = s2.charAt(i);
-                break;
-            }
-        }
-        return ans == '0' ? s2.charAt(s2.length()-1) : ans;
+class Solution {
+  public char findTheDifference(String s, String t) {
+    int[] counter = new int[26];
+    for (char c : s.toCharArray()) {
+      counter[c - 'a']++;
     }
-    
-    public String sortString(String s) {
-        char[] chars = s.toCharArray();
-        Arrays.sort(chars);
-        String sorted = new String(chars);
-        return sorted;
+    for (char c : t.toCharArray()) {
+      if (counter[c - 'a'] == 0) {
+        return c;
+      }
+      counter[c - 'a']--;
     }
-}
+    return '-';
+  }
+}
diff --git a/Easy/Increasing Decreasing String.java b/Easy/Increasing Decreasing String.java
@@ -0,0 +1,32 @@
+class Solution {
+  public String sortString(String s) {
+    int[] counter = new int[26];
+    for (char c : s.toCharArray()) {
+      counter[c - 'a']++;
+    }
+    StringBuilder sb = new StringBuilder();
+    while (sb.length() != s.length()) {
+      addLowerToHiger(sb, counter);
+      addHigherToLower(sb, counter);
+    }
+    return sb.toString();
+  }
+  
+  private void addLowerToHiger(StringBuilder sb, int[] counter) {
+    for (int i = 0; i < 26; i++) {
+      if (counter[i] != 0) {
+        sb.append((char) (97 + i));
+        counter[i]--;
+      }
+    }
+  }
+  
+  private void addHigherToLower(StringBuilder sb, int[] counter) {
+    for (int i = 25; i >= 0; i--) {
+      if (counter[i] != 0) {
+        sb.append((char) (97 + i));
+        counter[i]--;
+      }
+    }
+  }
+}
