《Cracking the Coding Interview》——第18章：难题——题目5

 1 // 18.5 Given a text file containing words, find the shortest distance between two words.
 2 #include <algorithm>
 3 #include <climits>
 4 using namespace std;
 5 
 6 struct ListNode {
 7     int val;
 8     ListNode *next;
 9     ListNode(int _val = 0): val(_val), next(nullptr) {};
10 };
11 
12 class Solution {
13 public:
14     int minDist(ListNode *head1, ListNode *head2)
15     {
16         // the two list records the forward indices of two word, i.e. their occurrence position.
17         // For example, 1->4->5->nullptr means the word appears at 1st, 4th and 5th line.
18         
19         int min_dist = INT_MAX;
20         ListNode *p1, *p2;
21         
22         p1 = head1;
23         p2 = head2;
24         while (p1 != nullptr && p2 != nullptr) {
25             if (p1->val < p2->val) {
26                 min_dist = min(min_dist, p2->val - p1->val);
27                 p1 = p1->next;
28             } else {
29                 min_dist = min(min_dist, p1->val - p2->val);
30                 p2 = p2->next;
31             }
32         }
33         
34         return min_dist;
35     }
36 };