Solved 3 problems

varunu28 · varunu28 · commit ef3ba2862c63 · 2017-12-05T17:45:45.000-08:00
diff --git a/Easy/Add Binary.java b/Easy/Add Binary.java
@@ -0,0 +1,49 @@
+class Solution {
+    public String addBinary(String a, String b) {
+        int maxL = Math.max(a.length(), b.length());
+        
+        if (a.length() < maxL) {
+            a = String.join("", Collections.nCopies(maxL - a.length(), "0")) + a;
+        }
+        
+        if (b.length() < maxL) {
+            b = String.join("", Collections.nCopies(maxL - b.length(), "0")) + b;
+        }
+        
+        int carry = 0;
+        StringBuilder sb = new StringBuilder("");
+        
+        for (int i=a.length()-1;i>=0;i--) {
+            if (a.charAt(i) == '1' && b.charAt(i) == '1') {
+                if (carry == 1) {
+                    sb.append("1");
+                }
+                else {
+                    sb.append("0");
+                }
+                
+                carry  = 1;
+            }
+            
+            else if (a.charAt(i) == '0' && b.charAt(i) == '0') {
+                sb.append(String.valueOf(carry));
+                carry = 0;
+            }
+            
+            else if (a.charAt(i) != b.charAt(i)) {
+                if (carry == 1) {
+                    sb.append("0");
+                }
+                else {
+                    sb.append("1");
+                }
+            }
+        }
+        
+        if (carry == 1) {
+            sb.append("1");
+        }
+        
+        return sb.reverse().toString();
+    }
+}
diff --git a/Easy/Plus One.java b/Easy/Plus One.java
@@ -0,0 +1,35 @@
+class Solution {
+    public int[] plusOne(int[] digits) {
+        
+        int carry = 1;
+        List<Integer> ans = new ArrayList<>();
+        
+        for (int i=digits.length-1;i>=0;i--) {
+            if (digits[i] == 9 && carry == 1) {
+                ans.add(0);
+                carry  = 1;
+            }
+            else if (carry == 1) {
+                ans.add(digits[i]+carry);
+                carry = 0;
+            }
+            else {
+                ans.add(digits[i]+carry);
+            }
+        }
+        
+        if (carry!=0) {
+            ans.add(carry);
+        }
+        
+        Collections.reverse(ans);
+        
+        int [] a = new int[ans.size()];
+        
+        for (int k=0; k<ans.size();k++) {
+            a[k] = ans.get(k);
+        }
+        
+        return a;
+    }
+}
diff --git a/Easy/Ransom Note.java b/Easy/Ransom Note.java
@@ -0,0 +1,35 @@
+class Solution {
+    public boolean canConstruct(String ransomNote, String magazine) {
+        Map<Character, Integer> noteMap = new HashMap<>();
+        Map<Character, Integer> magMap = new HashMap<>();
+        
+        for(char c: ransomNote.toCharArray()) {
+            if (noteMap.containsKey(c)) {
+                noteMap.put(c, noteMap.get(c) + 1);
+            }
+            else {
+                noteMap.put(c, 1);
+            }
+        }
+        
+        for(char c: magazine.toCharArray()) {
+            if (magMap.containsKey(c)) {
+                magMap.put(c, magMap.get(c) + 1);
+            }
+            else {
+                magMap.put(c, 1);
+            }
+        }
+        
+        for (Map.Entry<Character, Integer> entry: noteMap.entrySet()) {
+            if (magMap.containsKey(entry.getKey()) && magMap.get(entry.getKey()) >= entry.getValue()) {
+                continue;
+            }
+            else {
+                return false;
+            }
+        }
+        
+        return true;
+    }
+}
