Create Number of Pairs of Strings With Concatenation Equal to Target.java

varunu28 · web-flow · commit 9728a5baad19 · 2021-10-06T07:57:59.000-05:00
diff --git a/Medium/Number of Pairs of Strings With Concatenation Equal to Target.java b/Medium/Number of Pairs of Strings With Concatenation Equal to Target.java
@@ -0,0 +1,18 @@
+class Solution {
+  public int numOfPairs(String[] nums, String target) {
+    Map<String, Integer> map = new HashMap<>();
+    int count = 0;
+    for (String num : nums) {
+      if (target.startsWith(num)) {
+        String end = target.substring(num.length());
+        count += map.getOrDefault(end, 0);
+      } 
+      if (target.endsWith(num)) {
+        String start = target.substring(0, target.length() - num.length());
+        count += map.getOrDefault(start, 0);
+      }
+      map.put(num, map.getOrDefault(num, 0) + 1);
+    }
+    return count;
+  }
+}
