Added 3 solutions

varunu28 · varunu28 · commit 10885cbddbd8 · 2018-09-25T14:08:06.000-07:00
diff --git a/Easy/Letter Case Permutation.java b/Easy/Letter Case Permutation.java
@@ -0,0 +1,23 @@
+class Solution {
+    public List<String> letterCasePermutation(String S) {
+        List<String> ans = new ArrayList<>();
+        letterCasePermutationHelper(ans, S.toCharArray(), 0);
+
+        return ans;
+    }
+
+    private void letterCasePermutationHelper(List<String> ans, char[] chars, int index) {
+        if (index == chars.length) {
+            ans.add(new String(chars));
+        }
+        else {
+            if (Character.isLetter(chars[index])) {
+                chars[index] = Character.toLowerCase(chars[index]);
+                letterCasePermutationHelper(ans, chars, index+1);
+                chars[index] = Character.toUpperCase(chars[index]);
+            }
+
+            letterCasePermutationHelper(ans, chars, index+1);
+        }
+    }
+}
diff --git a/Easy/Number of Lines To Write String.java b/Easy/Number of Lines To Write String.java
@@ -0,0 +1,21 @@
+class Solution {
+    public static int[] numberOfLines(int[] widths, String S) {
+        if (S.isEmpty()) {
+            return new int[]{0,0};
+        }
+
+        int capacity = 100;
+        char[] chars = S.toCharArray();
+        int count = 1;
+
+        for (char c : chars) {
+            if (capacity - widths[c-'a'] < 0) {
+                capacity = 100;
+                count++;
+            }
+            capacity -= widths[c-'a'];
+        }
+
+        return new int[]{count, 100-capacity};
+    }
+}
diff --git a/Medium/Contiguous Array.java b/Medium/Contiguous Array.java
@@ -0,0 +1,20 @@
+class Solution {
+    public int findMaxLength(int[] nums) {  
+        Map<Integer, Integer> map = new HashMap<>();
+        map.put(0, -1);
+        int maxLen = 0;
+        int count = 0;
+        
+        for (int i=0; i<nums.length; i++) {
+            count += nums[i] == 0 ? -1 : 1;
+            if (map.containsKey(count)) {
+                maxLen = Math.max(maxLen, i-map.get(count));
+            }
+            else {
+                map.put(count, i);
+            }
+        }
+        
+        return maxLen;
+    }
+}
