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#include<vector>
#include<iostream>
#include<stack>
#include<queue>
#include<algorithm>
#include<unordered_map>
using namespace std;
struct GraphNode {
string name;
vector<GraphNode*> children;
unordered_map<string, double> values;
void addChildren(GraphNode* node, double val) {
children.push_back(node);
values[node->name] = val;
}
GraphNode(string name0): name(name0) {}
};
class Solution {
public:
unordered_map<string, int> index;
vector<GraphNode*> g;
int len;
vector<double> calcEquation(vector<vector<string>>& equations, vector<double>& values, vector<vector<string>>& queries) {
int equationNum = equations.size();
int count = 0;
for(int i = 0; i < equationNum; i++) {
string node1Name = equations[i][0],node2Name = equations[i][1];
double value1 = values[i], value2 = 1/values[i];
GraphNode *node1, *node2;
if(index.count(node1Name) == 0) {
node1 = new GraphNode(node1Name);
index[node1Name] = count++;
g.push_back(node1);
} else {
node1 = g[index[node1Name]];
}
if(index.count(node2Name) == 0) {
node2 = new GraphNode(node2Name);
index[node2Name] = count++;
g.push_back(node2);
} else {
node2 = g[index[node2Name]];
}
node1->addChildren(node2, value1);
node2->addChildren(node1, value2);
}
printG();
len = g.size();
vector<double> res;
for(auto query : queries) {
res.push_back(search(query[0], query[1]));
}
return res;
}
void printG() {
for(auto node : g) {
cout << node->name << ": ";
int size = node->children.size();
for(int i = 0; i < size; i++) {
cout << "(" << node->children[i]->name << " | " << node->values[node->children[i]->name] << "), ";
}
cout << endl;
}
}
double search(const string& s, const string& e) {
if(index.count(e) == 0 || index.count(s) == 0) return -1.0;
int target = index[e];
int start = index[s];
if(start == target) return 1.0;
vector<bool> visited(len, false);
stack<pair<int, double>> q;
q.push(pair<int, double>(start, 1.0));
visited[start] = true;
double res = 1.0;
while(!q.empty()) {
int nodeIndex = q.top().first;
double val = q.top().second;
res *= val;
GraphNode* node = g[nodeIndex];
bool add = false;
q.pop();
for(GraphNode* child : node->children) {
int childIndex = index[child->name];
if(childIndex == target) {
return res * node->values[child->name];
} else if(!visited[childIndex]) {
q.push(pair<int, double>(childIndex, node->values[child->name]));
visited[childIndex] = true;
add = true;
}
}
if(!add) {
res /= val;
}
}
return -1.0;
}
};
template<class T>
void printVec(const vector<T> &v, const string& head = "")
{
if(head != "") {
cout << head << ": ";
}
for (T i : v)
{
cout << i << " ";
}
cout << "\n";
}
int main() {
Solution s;
vector<vector<string>> equations = {{"a","e"},{"b","e"}};
vector<double> values = {4.0,3.0};
vector<vector<string>> queries = {{"a","b"},{"e","e"},{"x","x"}};
vector<double> res = s.calcEquation(equations, values, queries);
printVec<double>(res, "result = ");
return 0;
}
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