-
Notifications
You must be signed in to change notification settings - Fork 0
/
241.hpp
79 lines (66 loc) · 1.96 KB
/
241.hpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
#ifndef LEETCODE_241_HPP
#define LEETCODE_241_HPP
#include <iostream>
#include <queue>
#include <algorithm>
#include <vector>
#include <unordered_map>
#include <unordered_set>
#include <set>
#include <numeric>
#include <stack>
#include <string>
using namespace std;
/*
Given a string of numbers and operators,
return all possible results from computing all the different possible ways to group numbers and operators.
The valid operators are +, - and *.
Example 1
Input: "2-1-1".
((2-1)-1) = 0
(2-(1-1)) = 2
Output: [0, 2]
Example 2
Input: "2*3-4*5"
(2*(3-(4*5))) = -34
((2*3)-(4*5)) = -14
((2*(3-4))*5) = -10
(2*((3-4)*5)) = -10
(((2*3)-4)*5) = 10
Output: [-34, -14, -10, -10, 10]
*/
class Solution {
public:
vector<int> diffWaysToCompute(string input) {
unordered_map<string, vector<int>> memo;
return diffWaysWithMemo(memo, input);
}
private:
vector<int> diffWaysWithMemo(unordered_map<string, vector<int>> &memo, string input) {
if (memo.count(input))
return memo[input];
vector<int> result;
for (int i = 0; i < input.size(); ++i) {
char cur = input[i];
if (cur == '+' || cur == '-' || cur == '*') {
vector<int> v1 = diffWaysWithMemo(memo, input.substr(0, static_cast<unsigned long>(i)));
vector<int> v2 = diffWaysWithMemo(memo, input.substr(static_cast<unsigned long>(i + 1)));
for (int n1 : v1) {
for (int n2: v2) {
if (cur == '+')
result.push_back(n1 + n2);
else if (cur == '-')
result.push_back(n1 - n2);
else
result.push_back(n1 * n2);
}
}
}
}
if (result.empty())
result.push_back(atoi(input.c_str()));
memo[input] = result;
return result;
}
};
#endif //LEETCODE_241_HPP