biweekly contest 112

update the solutions

Author: longluo

Java/src/com/longluo/contest/biweekly_contest_112/Problem1.java

@@ -50,8 +50,38 @@ public static boolean canBeEqual(String s1, String s2) {
         return true;
     }
 
+    public static boolean canBeEqual_bf(String s1, String s2) {
+        boolean[] masks = new boolean[4];
+
+        for (int i = 0; i < 4; i++) {
+            char ch = s1.charAt(i);
+
+            boolean flag = false;
+
+            for (int j = 0; j < 4; j += 2) {
+                int loc = (i + j) % 4;
+
+                if (!masks[loc] && s2.charAt(loc) == ch) {
+                    flag = true;
+                    masks[loc] = true;
+                    break;
+                }
+            }
+
+            if (!flag) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
     public static void main(String[] args) {
         System.out.println("true ?= " + canBeEqual("abcd", "cdab"));
         System.out.println("false ?= " + canBeEqual("abcd", "dacb"));
+
+        System.out.println("true ?= " + canBeEqual_bf("abcd", "abcd"));
+        System.out.println("true ?= " + canBeEqual_bf("abcd", "cdab"));
+        System.out.println("false ?= " + canBeEqual_bf("abcd", "dacb"));
     }
 }

Java/src/com/longluo/contest/biweekly_contest_112/Problem2.java

@@ -10,26 +10,26 @@ public static boolean checkStrings(String s1, String s2) {
             return true;
         }
 
-        int[] oddcnt1 = new int[26];
-        int[] oddcnt2 = new int[26];
+        int len = s1.length();
 
-        int[] evencnt1 = new int[26];
-        int[] evencnt2 = new int[26];
+        int[] odd1 = new int[26];
+        int[] even1 = new int[26];
 
-        int n = s1.length();
+        int[] odd2 = new int[26];
+        int[] even2 = new int[26];
 
-        for (int i = 0; i < n; i += 2) {
-            evencnt1[s1.charAt(i) - 'a']++;
-            evencnt2[s2.charAt(i) - 'a']++;
-        }
-
-        for (int i = 1; i < n; i += 2) {
-            oddcnt1[s1.charAt(i) - 'a']++;
-            oddcnt2[s2.charAt(i) - 'a']++;
+        for (int i = 0; i < len; i++) {
+            if (i % 2 == 0) {
+                even1[s1.charAt(i) - 'a']++;
+                even2[s2.charAt(i) - 'a']++;
+            } else {
+                odd1[s1.charAt(i) - 'a']++;
+                odd2[s2.charAt(i) - 'a']++;
+            }
         }
 
         for (int i = 0; i < 26; i++) {
-            if (oddcnt1[i] != oddcnt2[i] || evencnt1[i] != evencnt2[i]) {
+            if (odd1[i] != odd2[i] || even1[i] != even2[i]) {
                 return false;
             }
         }

Java/src/com/longluo/contest/biweekly_contest_112/Problem3.java

@@ -10,43 +10,49 @@ public class Problem3 {
     public static long maxSum(List<Integer> nums, int m, int k) {
         int n = nums.size();
 
-        long max = 0;
+        Map<Integer, Integer> countMap = new HashMap<>();
 
         long sum = 0;
 
-        Map<Integer, Integer> map = new HashMap<>();
-
         for (int i = 0; i < k; i++) {
-            sum += nums.get(i);
-            map.put(nums.get(i), map.getOrDefault(nums.get(i), 0) + 1);
+            int value = nums.get(i);
+            sum += value;
+            countMap.put(value, countMap.getOrDefault(value, 0) + 1);
         }
 
-        if (map.size() >= m) {
-            max = Math.max(max, sum);
+        long ans = 0;
+
+        if (countMap.size() >= m) {
+            ans = Math.max(ans, sum);
         }
 
         int left = 0;
         int right = k;
 
         while (left < right && right < n) {
-            map.put(nums.get(right), map.getOrDefault(nums.get(right), 0) + 1);
+            int rVal = nums.get(right);
+
+            countMap.put(rVal, countMap.getOrDefault(rVal, 0) + 1);
             sum += nums.get(right);
-            if (map.get(nums.get(left)) > 1) {
-                map.put(nums.get(left), map.getOrDefault(nums.get(left), 0) - 1);
+
+            int lVal = nums.get(left);
+
+            if (countMap.get(lVal) > 1) {
+                countMap.put(lVal, countMap.getOrDefault(lVal, 0) - 1);
             } else {
-                map.remove(nums.get(left));
+                countMap.remove(lVal);
             }
             sum -= nums.get(left);
 
-            if (map.size() >= m) {
-                max = Math.max(max, sum);
+            if (countMap.size() >= m) {
+                ans = Math.max(ans, sum);
             }
 
             left++;
             right++;
         }
 
-        return max;
+        return ans;
     }
 
     public static void main(String[] args) {