Given a string num that contains only digits and an integer target, return all possibilities to insert the binary operators '+', '-', and/or '*' between the digits of num so that the resultant expression evaluates to the target value.
Note that operands in the returned expressions should not contain leading zeros.
Note that a number can contain multiple digits.
Examples
Example 1
Input: num = "123", target = 6
Output: ["1*2*3","1+2+3"]
Explanation: Both "1*2*3" and "1+2+3" evaluate to 6.
Example 2
Input: num = "232", target = 8
Output: ["2*3+2","2+3*2"]
Explanation: Both "2*3+2" and "2+3*2" evaluate to 8.
Example 3
Input: num = "3456237490", target = 9191
Output: []
Explanation: There are no expressions that can be created from "3456237490" to evaluate to 9191.
Constraints
1 <= num.length <= 10
num consists of only digits.
-231 <= target <= 231 - 1
282. Expression Add Operators
Hard
50 Points
Math
String
Backtracking
Given a string num that contains only digits and an integer target, return all possibilities to insert the binary operators '+', '-', and/or '*' between the digits of num so that the resultant expression evaluates to the target value.
Note that operands in the returned expressions should not contain leading zeros.
Note that a number can contain multiple digits.
Examples
Example 1
Input: num = "123", target = 6
Output: ["1*2*3","1+2+3"]
Explanation: Both "1*2*3" and "1+2+3" evaluate to 6.
Example 2
Input: num = "232", target = 8
Output: ["2*3+2","2+3*2"]
Explanation: Both "2*3+2" and "2+3*2" evaluate to 8.
Example 3
Input: num = "3456237490", target = 9191
Output: []
Explanation: There are no expressions that can be created from "3456237490" to evaluate to 9191.
Constraints
1 <= num.length <= 10
num consists of only digits.
-231 <= target <= 231 - 1
Expression Add Operators - Practice Coding | SlaveCode