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#include "leetcode.h"
class Solution {
public:
vector<double> calcEquation(vector<vector<string>> &equations,
vector<double> &values,
vector<vector<string>> &queries) {
vector<double> ans;
map<string, double> mp;
map<string, vector<string>> graph;
for (int i = 0; i < equations.size(); i++) {
string u = equations[i][0], v = equations[i][1];
mp[u + "->" + v] = values[i];
mp[v + "->" + u] = 1 / values[i];
graph[u].push_back(v);
graph[v].push_back(u);
}
for (int i = 0; i < queries.size(); i++) {
string start = queries[i][0], end = queries[i][1];
if (graph.find(start) == graph.end() || graph.find(end) == graph.end()) {
ans.push_back(-1);
} else {
double val = 1;
map<string, int> visited;
bool found = false;
if (start == end)
found = true;
else
dfs(start, end, mp, graph, val, visited, found);
if (found == true)
ans.push_back(val);
else
ans.push_back(-1);
}
}
return ans;
}
private:
void dfs(string start, string end, map<string, double> &mp,
map<string, vector<string>> &graph, double &val,
map<string, int> &visited, bool &found) {
visited[start] = 1;
if (found == true)
return;
for (auto child : graph[start]) {
if (visited[child] != 1) {
val *= mp[start + "->" + child];
if (end == child) {
found = true;
return;
}
dfs(child, end, mp, graph, val, visited, found);
if (found == true)
return;
else
val /= mp[start + "->" + child];
}
}
}
};
int main() {}
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