qrealka · May 5, 2020 00:09 · May 5, 2020
diff --git a/inplace_rle.cpp b/inplace_rle.cpp
@@ -0,0 +1,35 @@
+class Solution {
+public:
+    int compress(vector<char>& chars) {
+        int n = chars.size();
+        if (n <= 1) return n;
+        int j = 0, i = 0;
+        while (i < n) {
+            int k = i;
+            // skip duplicates
+            while ((k + 1 < n) && chars[k] == chars[k + 1]) {
+                k ++;
+            }
+            // compute the repeat count
+            int count = k - i + 1;
+            // fill the character first
+            chars[j ++] = chars[i];
+            // skip writting 1 as counter
+            if (count == 1) {
+                i ++;
+                continue;
+            }
+            // write out the reversed 'counter'
+            int start = j;
+            while (count > 0) {
+                chars[j ++] = (char)(48 + (count % 10));
+                count /= 10;
+            }
+            // reverse the counter e.g. if (count >= 10)
+            std::reverse(begin(chars) + start, begin(chars) + j);
+            // navigate to next character
+            i = k + 1; 
+        }
+        return j;
+    }
+};