54 lines
1.3 KiB
C++
54 lines
1.3 KiB
C++
|
#include <queue>
|
||
|
|
#include <string>
|
||
|
|
#include <vector>
|
||
|
|
|
||
|
|
class Solution {
|
||
|
|
public:
|
||
|
|
int openLock(const std::vector<std::string> &deadends,
|
||
|
|
const std::string &target) {
|
||
|
|
std::vector<bool> visited(10000);
|
||
|
|
for (const auto &end : deadends) {
|
||
|
|
visited[std::stoi(end)] = true;
|
||
|
|
}
|
||
|
|
|
||
|
|
// we're already starting with a dead end
|
||
|
|
if (visited[0]) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
auto t = std::stoi(target);
|
||
|
|
|
||
|
|
std::queue<std::pair<int, int>> q;
|
||
|
|
q.emplace(0, 0);
|
||
|
|
visited[0] = true;
|
||
|
|
|
||
|
|
while (!q.empty()) {
|
||
|
|
auto [steps, comb] = q.front();
|
||
|
|
q.pop();
|
||
|
|
|
||
|
|
// found the target
|
||
|
|
if (comb == t) {
|
||
|
|
return steps;
|
||
|
|
}
|
||
|
|
|
||
|
|
auto comb_tmp = comb;
|
||
|
|
for (auto d = 1; d < 10000; d *= 10) {
|
||
|
|
auto digit = comb_tmp % 10;
|
||
|
|
comb_tmp /= 10;
|
||
|
|
|
||
|
|
for (auto i : {-1, 1}) {
|
||
|
|
auto next_digit = (digit + i + 10) % 10;
|
||
|
|
auto next_comb = comb + (next_digit - digit) * d;
|
||
|
|
|
||
|
|
if (!visited[next_comb]) {
|
||
|
|
q.emplace(steps + 1, next_comb);
|
||
|
|
visited[next_comb] = true;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
};
|