990.cpp

/**
 *    author:   vulkan
 *    created:  13.08.2020 11:27:42 PM
**/
#include <bits/stdc++.h>

using namespace std;

class dsu_t {
    int n;
    vector<int> parent;
public:
    dsu_t(int n);
    int find(int x);
    void merge(int x, int y);
    bool check(int x, int y);
};

dsu_t::dsu_t(int n) {
    this->n = n;
    parent = vector<int>(n);
    for (int i = 0; i <= n - 1; ++i) {
        parent[i] = i;
    }
}

int dsu_t::find(int x) {
    return x == this->parent[x] ? x : this->parent[x] = this->find(parent[x]);
}

void dsu_t::merge(int x, int y) {
    this->parent[this->find(x)] = this->find(y);
}

bool dsu_t::check(int x, int y) {
    return this->find(x) == this->find(y);
}

bool equationsPossible(vector<string> &equations) {
    dsu_t dsu(26);
    for (string eq : equations) {
        if (eq[1] == '=') {
            int x = eq[0] - 'a', y = eq[3] - 'a';
            dsu.merge(x, y);
        }
    }

    for (string eq : equations) {
        if (eq[1] == '!') {
            int x = eq[0] - 'a', y = eq[3] - 'a';
            if (dsu.check(x, y)) {
                return false;
            }
        }
    }

    return true;
}

int main(int argc, char const *argv[]) {
    int n;
    cin >> n;
    vector<string> equations(n);
    for (int i = 0; i <= n - 1; ++i) {
        cin >> equations[i];
    }

    cout << equationsPossible(equations);

    return 0;
}