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
|
// 514. Freedom Trail
#include "leetcode.h"
/*
* in the video game fallout 4, the quest "road to freeom" requires players to
* reach a metal dial call the "freedom trail ring" and use the dial to spell a
* specific keyword to open the door. given a string 'rint' that represents the
* code engraved on the outer ring and another string 'key' that represents the
* keyword that needs to be spelled, return the minimum number of steps to spell
* all of the characters in the keyword. initially, the first character of the
* ring is aligned at "12:00" diretion. you should spell all the characters in
* 'key' one by rotating 'ring' clockwise or anticlockwise to make each
* character of the string aligned at the "12:00" direction and then by pressing
* the center button. at the stage of rotating the ring to spell the key
* character 'key[i]' you can rotate the ring clockwise or anticlockwise by one
* place, which counts as one step. the final purpose of the rotation is to
* align one of 'ring's characters at "12:00" direction, where this character
* must equal 'key[i]'
*/
class Solution {
public:
int findRotateSteps(string ring, string key) {
int n = ring.size();
unordered_map<char, vector<int>> idx_map;
for (int i = 0; i < n; ++i)
idx_map[ring[i]].push_back(i);
vector<vector<pair<int, int>>> dp(key.size());
for (int i : idx_map[key[0]]) {
int dist = min(i, n - i);
dp[0].push_back({i, dist});
}
int min_sum = INT_MAX;
for (int i = 1; i < key.size(); ++i) {
for (int idx : idx_map[key[i]]) {
int min_dist = INT_MAX;
for (auto &pair : dp[i - 1]) {
int abs_dist = abs(pair.first - idx);
int dist = min(abs_dist, n - abs_dist);
min_dist = min(min_dist, dist + pair.second);
}
dp[i].push_back({idx, min_dist});
if (i == key.size() - 1)
min_sum = min(min_dist, min_sum);
}
}
return min_sum + key.size();
}
};
int main() {
Solution obj;
printf("%d\n", obj.findRotateSteps("godding", "gd")); // expect: 4
printf("%d\n", obj.findRotateSteps("godding", "godding")); // expect: 13
}
|