x1 != x2

#include <bits/stdc++.h>

const int MAX = 100000;
const int M = 50;
char first[M], second[M], sign[3];
int n, m, k = 0, parent[MAX];
std::pair<int, int> not_equal[MAX];

inline int __attribute__((always_inline)) to_int(char *str) {
    return atoi(str + 1) - 1;
}

int find_set(int v) {
    if (v == parent[v])
        return v;
    return parent[v] = find_set(parent[v]);
}

void union_sets(int a, int b) {
    a = find_set(a);
    b = find_set(b);
    if (a != b)
        parent[b] = a;
}

void read() {
    freopen("equal-not-equal.in", "r", stdin);
    freopen("equal-not-equal.out", "w", stdout);
    scanf("%d%d", &n, &m);
    for (int i = 0; i < n; ++i) {
        parent[i] = i;
    }
    for (int i = 0; i < m; ++i) {
        scanf("%s%s%s", first, sign, second);
        int x = to_int(first);
        int y = to_int(second);
        if (!strcmp(sign, "!=")) {
            not_equal[k].first = x;
            not_equal[k++].second = y;
            continue;
        }
        union_sets(x, y);
    }
}

void solve() {
    for(int i = 0; i < k; ++i) {
        int x = find_set(not_equal[i].first);
        int y = find_set(not_equal[i].second);
        if(x == y) {
            printf("No");
            return;
        }
    }
    printf("Yes");
}

int main() {
    read();
    solve();
}