HardNo. 1320
Minimum Distance to Type a Word Using Two Fingers — LeetCode 1320 Python Solution
- Pattern
- Dynamic Programming
- Topics
- String, Dynamic Programming
- Reading time
- 5 min
- Source
- leetcode.com
The problem
You have a keyboard layout as shown above in the X-Y plane, where each English uppercase letter is located at some coordinate. For example, the letter 'A' is located at coordinate (0, 0), the letter 'B' is located at coordinate (0, 1), the letter 'P' is located at coordinate (2, 3) and the letter 'Z' is located at coordinate (4, 1).
Example
- Input
- word = "CAKE"
- Output
- 3
- Explanation
- Using two fingers, one optimal way to type "CAKE" is:
Python solution
class Solution:
def minimumDistance(self, word: str) -> int:
def dist(a: int, b: int) -> int:
x1, y1 = divmod(a, 6)
x2, y2 = divmod(b, 6)
return abs(x1 - x2) + abs(y1 - y2)
n = len(word)
f = [[[inf] * 26 for _ in range(26)] for _ in range(n)]
for j in range(26):
f[0][ord(word[0]) - ord('A')][j] = 0
f[0][j][ord(word[0]) - ord('A')] = 0
for i in range(1, n):
a, b = ord(word[i - 1]) - ord('A'), ord(word[i]) - ord('A')
d = dist(a, b)
for j in range(26):
f[i][b][j] = min(f[i][b][j], f[i - 1][a][j] + d)
f[i][j][b] = min(f[i][j][b], f[i - 1][j][a] + d)
if j == a:
for k in range(26):
t = dist(k, b)
f[i][b][j] = min(f[i][b][j], f[i - 1][k][a] + t)
f[i][j][b] = min(f[i][j][b], f[i - 1][a][k] + t)
a = min(f[n - 1][ord(word[-1]) - ord('A')])
b = min(f[n - 1][j][ord(word[-1]) - ord('A')] for j in range(26))
return int(min(a, b))Complexity
- Time
- O(n × |Σ|2)
- Space · auxiliary
- O(n × |Σ|2)
Pattern: Dynamic Programming
Define a state, write the transition, and stop recomputing the same subproblem. LeetCode 1320. Minimum Distance to Type a Word Using Two Fingers is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Dynamic Programming.
The dynamic programming guide has the Python template for the pattern and the 481 LeetCode problems that use it.
Related problems
| No. | Problem | Difficulty |
|---|---|---|
| 1312 | Minimum Insertion Steps to Make a String Palindrome | Hard |
| 0010 | Regular Expression Matching | Hard |
| 0022 | Generate Parentheses | Medium |
| 0032 | Longest Valid Parentheses | Hard |
| 0044 | Wildcard Matching | Hard |
| 0072 | Edit Distance | Medium |
Frequently asked questions
- How hard is LeetCode 1320. Minimum Distance to Type a Word Using Two Fingers?
LeetCode 1320. Minimum Distance to Type a Word Using Two Fingers is rated Hard on LeetCode.
- What is the time complexity of LeetCode 1320. Minimum Distance to Type a Word Using Two Fingers?
The Python solution on this page runs in O(n × |Σ|2).
- What is the space complexity of LeetCode 1320. Minimum Distance to Type a Word Using Two Fingers?
The Python solution on this page uses O(n × |Σ|2) auxiliary space.
- What topics does LeetCode 1320. Minimum Distance to Type a Word Using Two Fingers cover?
LeetCode 1320. Minimum Distance to Type a Word Using Two Fingers is tagged String and Dynamic Programming on LeetCode.