316. Remove Duplicate Letters

⛳ Overview

Given a string s, remove duplicate letters so that every letter appears once and only once. You must make sure your result is the smallest in lexicographical order among all possible results.

Example 1:

Input: s = "bcabc"
Output: "abc"


Example 2:

Input: s = "cbacdcbc"
Output: "acdb"

Constraints:

• 1 <= s.length <= 104
• s consists of lowercase English letters.

📃 Analysis

tip

Separate the question into 3 parts

• remove duplicates
• keep the order

✏ Code Editor

Live Editor

function removeDuplicateLetters(s) { let stack = []; for (let i = 0; i < s.length; i++) { if (stack.indexOf(s[i]) !== -1) continue; while (stack.length && stack[stack.length - 1] > s[i] && s.indexOf(stack[stack.length - 1], i) !== -1) { stack.pop(); } stack.push(s[i]) } return stack.join("") }; const testCases=["bcabc","cbacdcbc"] render( <TestRun codeFn= {removeDuplicateLetters} testCases={testCases} /> )

function removeDuplicateLetters(s) {
  let stack = [];
  for (let i = 0; i < s.length; i++) {
    if (stack.indexOf(s[i]) !== -1) continue;
    while (stack.length && stack[stack.length - 1] > s[i] && s.indexOf(stack[stack.length - 1], i) !== -1) {
      stack.pop();
    }
    stack.push(s[i])
  }
  return stack.join("")
};

const testCases=["bcabc","cbacdcbc"]

render(
  <TestRun
    codeFn= {removeDuplicateLetters}
    testCases={testCases}
  />
)

Result

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