LeetCode: Word Ladder

直接看答案。。
 1 class Solution {
 2 public:
 3     int ladderLength(string start, string end, unordered_set<string> &dict) {
 4         // Start typing your C/C++ solution below
 5         // DO NOT write int main() function
 6         if (start.size() != end.size() || !dict.size()) return 0;
 7         int dis = 1;
 8         queue<string> queTopush, queTopop;
 9         queTopop.push(start);
10         while (dict.size() && !queTopop.empty()) {
11             while (!queTopop.empty()) {
12                 string str = queTopop.front();
13                 queTopop.pop();
14                 for (int i = 0; i < str.size(); i++) {
15                     for (char j = 'a'; j <= 'z'; j++) {
16                         if (j == str[i]) continue;
17                         char tmp = str[i];
18                         str[i] = j;
19                         if (str == end) return dis+1;
20                         if (dict.count(str)) {
21                             queTopush.push(str);
22                             dict.erase(str);
23                         }
24                         str[i] = tmp;
25                     }
26                 }
27             }
28             queTopop.swap(queTopush);
29             dis++;
30         }
31         return 0;
32     }
33 };
posted @ 2013-04-23 02:29 ying_vincent 阅读(199) 评论(0) 收藏举报
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