feat: Solve permutation in string

      - Leetcode, #567

Author: brianr482

minimum-diff-sum.js

@@ -11,11 +11,10 @@ function findMinimumDiff(arr, remaining, accrued, size, maxSize) {
       findMinimumDiff([...arr, n], cloneArr, accrued + n, size + 1, maxSize);
     });
   }
-    if (arr.length > 0) {
-      min = Math.min(
-        Math.abs(accrued - remaining.reduce((a, b) => a + b, 0)), min
-      );
-    }
+  if (arr.length > 0) {
+    min = Math.min(
+      Math.abs(accrued - remaining.reduce((a, b) => a + b, 0)), min
+    );
   }
   var min = Infinity;
   findMinimumDiff([], A, 0, 1, A.length - 1);

permutation-in-string.js

@@ -0,0 +1,62 @@
+/**
+ * Leetcode, #567
+ * Given two strings s1 and s2, write a function to return true if s2 contains
+ * the permutation of s1. In other words, one of the first string's
+ * permutations is the substring of the second string.
+ * 
+ * Constraints:
+ * 1. The input strings only contain lower case letters.
+ * 2. The length of both given strings is in range [1, 10,000].
+*/
+
+/**
+ * @param {string} s1
+ * @param {string} s2
+ * @return {boolean}
+ */
+function checkInclusion(s1, s2) {
+  const regex = new RegExp(`[${s1}]`);
+  if (!s1 || !s2) {
+    return false;
+  }
+  if (s1.length > s2.length) {
+    return false;
+  }
+  if (!s2.match(regex)) {
+    return false;
+  }
+  const map = new Map();
+  s1.split('').forEach(ch => {        
+    map.set(ch, map.has(ch) ? map.get(ch) + 1 : 1);
+  });
+  const windowMap = new Map();
+  let matched = 0;
+  let l = 0;
+  let r = 0;
+  while (r < s2.length && l <= r) {
+    let lastLetter = s2.substr(r, 1);
+    windowMap.set(lastLetter, windowMap.has(lastLetter) ? windowMap.get(lastLetter) + 1 : 1);
+    if (map.has(lastLetter)) {
+      if (map.get(lastLetter) === windowMap.get(lastLetter)) {
+        matched++;
+        if (matched === map.size) {
+          return true;
+        }
+      } else if (windowMap.get(lastLetter) > map.get(lastLetter)) {
+        let letter = s2.substr(l, 1);
+        windowMap.set(letter, windowMap.get(letter) - 1);
+        if (map.has(letter) && map.get(letter) - windowMap.get(letter) === 1) {
+          matched--;
+        }
+        l++;
+      }
+      r++;
+    } else {
+      r++;
+      l = r;
+      matched = 0;
+      windowMap.clear();
+    }
+  }
+  return false;
+};