#2023
Number of Pairs of Strings With Concatenation Equal to Target
pupil · 495 · lc medium +27 · verified · 75.4% accepted · 748 likes · top 86%
Description
You have an array of digit strings nums and a digit string target. Count ordered pairs of indices (i, j) with i != j such that nums[i] concatenated with nums[j] equals target. Return that count.
Example 1:
Input: nums = ["777","7","77","77"], target = "7777"
Output: 4
Explanation: Valid pairs are:
- (0, 1): "777" + "7"
- (1, 0): "7" + "777"
- (2, 3): "77" + "77"
- (3, 2): "77" + "77"
Example 2:
Input: nums = ["123","4","12","34"], target = "1234"
Output: 2
Explanation: Valid pairs are:
- (0, 1): "123" + "4"
- (2, 3): "12" + "34"
Example 3:
Input: nums = ["1","1","1"], target = "11"
Output: 6
Explanation: Valid pairs are:
- (0, 1): "1" + "1"
- (1, 0): "1" + "1"
- (0, 2): "1" + "1"
- (2, 0): "1" + "1"
- (1, 2): "1" + "1"
- (2, 1): "1" + "1"
Code
1
2
3