June27: Lexi smallest string after substrings ops [M]

String manipulation of time O(N), and in-place update of O(1)

daily/June27.cpp

@@ -0,0 +1,28 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+class Solution {
+ public:
+  /**
+   * @brief LC: 2734: Lexicographically Smallest string after substring ops
+   * Time: O(N), Space: O(1), in-place update s of O(1) space
+   *
+   * @param s
+   * @return string
+   */
+  string smallestString(string s) {
+    int n = s.length();
+    for (int i = 0; i < n; i++) {
+      if (s[i] > 'a') {
+        // forward
+        for (; i < n && s[i] > 'a'; i++) {
+          s[i]--;
+        }
+        return s;
+      }
+    }
+    // all letter is 'a'
+    s.back() = 'z';
+    return s;
+  }
+};